Some Ideas
Ok so since I don't know what your limits are here's a few potential ideas.
Tie up your chest and if you like your breast such as that the rope/string etc. will be underneath your clothing. Just keep in mind to now go too tight so that you will somewhat comfortable for a period of unknown time. Then the crotch rope with knots places at the right spots and if it's not past your limits add a butt plug and/or insert something into your pussy before adding the crotch rope. Now get dressed and go out in public to do whatever you had planned to do that day. If you have never done anything like this before just keep safety in mind so don't plan to spend all day at school but maybe something like a trip to the grocery store so if the rope etc. gets to be too much from the rubbing etc. then you can quickly return home and remove it.
Something I see in the forums here a lot is cumming on pics humilition. Again all about limits but what I see is someone has a pic to share you pm them they send the pic. That other person then cums on the photo returns a photo of the result etc.
Also a challenge to accomplish here and there can be pretty fun and frustrating sometimes. You ask for a challenge, try to do it then post later (or pm) if you did it or not. If you failed you then get punished, if you succeeded you get rewarded. So if you want consider the first part of my reply as a challenge attempt to keep the crotch rope with knots on for let's say about 1 hour.