No amount of tissue in your pants will work, it's not absorbent enough, breaks down too easily and has no bulk. the better option there is to put socks or a smaller towel between two paris of pants but even that will leak without a waterproof cover, and if you don't want to use those things then there is not much choice for home made idea's
Telling them about your desires might work but can also go horribly wrong if they are not the open minded type..
Best bet would be to prepare a space in your room where you would be able to hide them (I for instance had a cupboard on a computer/work desk I had built which I specifically put a lock on.) something secure and/or well hidden. Then either go to a shop to buy some (limited choice) or order them online using a collection point. Most companies that sell diapers allow you to choose a collection point (often a local shop or post office etc.) to deliver to, you then go along when you get the notice it's arrived show them a barcode and pick it up.
Just keep the pack hidden and wear either when you are alone or if you feel comfortable just wear them, with even a little care for the clothes you wear on top they are not as easy to spot as most people worry about.
I and many others have managed to keep them hidden from people we live with for decades, the hardest part is disposing of them. just don't keep used ones laying around for long, buy some nappy sacks like
These, they are black and oaque. Pop it in there and into a trash bag already filling with rubbish to go straight out to the bin or into a backpack to throw away in a public bin when you go out somewhere,