When i was younger i used to wear tight rubber napies (dypers) under my jeans. you know the ones mothers put on babies. made of tranparent rubber and very tight.

I used to walk the streets, go on busses and trains and metro and just about everywhere, making sure they are skin tight, then i would drink lots of water and it felt SO sexy to piss myself and walk around within it in the daipers. then id go back and wash up :)