First off, if you're wearing a diaper but you pee like you normally would (that is, you wait until you have to go, then pee) you won't affect your continence at all. You're still holding it, the muscles are still doing the normal thing, you just get used to going in a diaper instead of walking over to the bathroom. Worst that might happen is that you do that for a while and forget that you're not diapered and have a small accident before you stop yourself. And even that's unlikely because your brain is still conscious of the fact that no diaper means not okay to pee.
If you wear and intentionally pee very frequently over an extended period of time (like months) without any breaks, you can maybe give yourself a minor form of urge incontinence because your muscles will atrophy. It's still a temporary thing though, a few days practicing holding it and you'll train the muscles back up. It's also really not healthy to do that, you're intentionally trying to mess your muscles up. Even then, though, people who have gone a long time wearing and using whenever they felt like it have said that they're still able to get back out of diapers pretty easily.
If you're into feeling incontinent, the best way to do it is to do something else to simulate the feeling. Get a friend (somebody on ADISC if you want) to randomly PM you telling you to have an accident, or schedule a free day where you'll have a lot to drink all day and have lots of desperation moments.