first of all: i dont want any pictures, but you will need an audience for this dare. whether they are right in front of you or not doesn't matter. yet i think you might get better results by doing it online.
with that said i hope this dare is ok by the rules.
This is again a two person dare though you might be able to pull it off being alone. you will want a larger group of viewers. A provider like stickam where you can watch your viewers might be the best for this there. now undress (visible or not is up to you) and turn on the vib. Set it to a power level which will not let you have an orgasm but keep you on the edge the whole time. Insert the whole vib inside yourself. Get the chastity belt and put it on.
Now comes the fun part: Your friend blindfolds you and gets a combination lock (those with the dials). He choses a random combination and memorizes it (better writes it down somewhere and takes the sheet with him). Now grab the webcam and give your audience a good and lenghty view of the combination before you set it to random.
Your friend now takes the sheet with him and leaves you for the duration of the show. You should now have a vib locked inside yourself and your audience is the having the combination to release you and you dont.
Have fun getting it back.
MODIFICATIONS:
if you have noone to trust with the combination, this shareware programm might help to stay locked for a certain time:
http://timelock.rules.it/
You also might play it as a timed dare and if you don't succeed you must do another dare (messy?)
If you really want some fun. get yourself a cheap prepaid mobile fun number you can publish on the net. get a vibrator called "the toy":
http://www.thetoy.co.uk/
Its an bluetooth dildo. so whenever someone (from the audience) writes you a sms you will really enjoy it. just make sure to publish the international number (00...) and change back to the original number once you are done.