Hmmmmm, first question, if best friend since 6th grade, then how come only friends for 4 years and you are 25?
Second, what are you hoping to get out of this? What is the goal in telling him? A lot of people will tell you to keep it in the room and to yourself except to your significant other, however there are others like me that feel like it can be a good thing to be open to others. Like you, I was tired of being secretive, and I wanted people to understand me better and know who I genuinely am. The other purpose though, which was more justified but just as important, was because I needed some support, somebody to talk to who I knew personally and could trust. If the reasons you want to tell are for reasons like this, then I can support you in opening up about it. If you are hoping for things like interaction between your friend and your little side though, then those reasons are bad, and not likely to occur, they could happen, but don't count on it.
Third, what does 'accept' mean to you? I only ask because your comment escalated quickly. If accept means that he hears you out, and respects you regardless, rather than makes fun of you and mocks you, then yes, if he doesn't accept you, then screw him.
However, if 'accept' means 'likes' then I would suggest that you be more careful with your actions, and perhaps screw you. Your friend should certainly be expected to be respectful towards your little side, however you may not find that your friend has much interest in discussing it unless necessary. Some friends will find that it is interesting, and interact with that side of yourself a little bit, but it certainly isn't something that should be expected, and not worth tossing a friendship out just because they won't make any references to the fact that you like diapers or feeling like a baby or whatever.
I remember the first friend that I told, and I was really close with him because I spent about 5 months with him constantly (literally). I thought, that since he had spent so much time with me, and was a really open minded person, and a psych major, that maybe he would be a really good guy to talk to about my little side (which he was), but part of myself also thought that it was a great idea, because I thought that since the amount of time I knew him for was much less than the rest of my friends, he was also an easier friend to risk loosing. I want to say this, because the 'screw him' comment: Please don't look at your friends as being expendable, it will make you feel awful afterwards when you do find that your friends accept you and are really cool about it, that they are just straight up great friends, and then you think about how ready you were to throw them out.
Yes, if your friend acts like an asshole to you because of your little side, then he is a bad friend, but for any other circumstance where you can respectfully remain friends, you should do so, and don't approach this with the attitude where you have an escape plan, you should approach this knowing that you can trust him/her and then treat him/her with that kind of respect.
As for step by step advice:
First: Question yourself why you are doing this, is it something that you feel like you need, and what do you hope to get out of it.
Second: Ask yourself, what type of person is my friend, is my friend pretty open minded, are we close enough to be sharing these types of things with each other? A really revealing question, though unrelated, "What is my friends opinion on homosexuals?" (I feel like this question is important for understanding how open minded they are since homosexuality is such a taboo in conservative thinking).
Third: Gage your friend's openness to hearing you out. Express to your friend the reason you would like to have a mature conversation with them. IE: "I was hoping I could share something with you really personal because...[I have been going through a tough time finding self acceptance]...[I feel like it would help me to open up to somebody about this]...[I just need to know that my best friends wouldn't freak out if they accidentally discovered my secret]...
Fourth: If your friend sounds open, engaged, and actually interested, proceed. If not, just say, "sorry, I didn't mean to make things awkward, I just need to get some things off my chest, but I want to keep things easy between us, i'll be fine."
Fifth: Rip the band-aid. Keep it small, simple, and direct, and then work your way from there. "I'm an adult baby," or "I like to wear diapers," or whatever best describes you in the most broad sense possible. (If you consider yourself AB, then go with "i'm an adult baby"). The reason I feel like ripping the band-aid off is best, is because it is so much easier to talk about it after that phrase is said. You can work your way backwards and explain what it all means in reference to you after that, but for the most part, people can kind of get a sense of what it means just by the phrase, rather than trying to put together an awkward image of you telling them little bits at a time.
So, that is my opinion on it all. So far I have told all of my close friends, and some not so close. The majority of my family knows too, but for the most part that is because there was massive family drama a while ago, and to match notes on everybody's experience, it was necessary for me to explain some context (my little side). Out of my experience, my first friend I told was very supportive, and actually helped me get through a lot of depression. My parents were really bad with it for the first few years, and it caused a lot of problems, but everything is pretty chill now. My friends that I live with are very supportive of it, and occasionally engage conversation about my little side. As for the rest of my friends and family, there is different levels of acceptance, some talk about it, some don't, but everybody has been respectful about it. Really the main thing that stops me from being totally open about it, is because I don't want anybody at my work knowing.
Let me finish with my reasons why I told.
1. I wanted my parents to know so they didn't have to get suspicious with my mail when I moved back in and would want to order diapers.
2. I wanted my parents and friends to understand why I might have trouble dating, in reference to me being an adult baby in a very conservative dating world.
3. I needed support because my parents had made my life hell for a little while.
4. I wanted to make sure that I could have a safe place to live when I moved into a place with friends, where I wouldn't have to fear about being driven out if they discovered my little side.
5. I felt like if people knew about it, maybe I would find less fear in my life by stopping my worry about if somebody was going to find out.
6. Maybe if people knew about my little side, then somebody I knew, would run across a girl who enjoyed things similar to AB life, and make a good match. Essentially widening my odds at finding the right girl.
7. I think that it is a stupid thing for people to be afraid of, and since for me it is a lifestyle, not just a fetish, I feel like it isn't nessiarily something that must be %100 contained in my room, i think it should be moderated. I feel like that being open about it helps drive a larger acceptance and awareness, and maybe one day people will be respectful towards it so hopefully young teens who realize that they are adult babies won't have to hide, get depressed, and feel like they are freaks.
