mmm, I think a forfeit that revolves around wanking should be your forfeit for wanking
EDIT for clarity
X = players remaining divided by 3 (so with 12 players remaining, x = 4)
You have to eat X soggy biscuits
Alternatively - and only allowed if eating ur own cum (eew) is a hard limit, then hand write out X*50 lines
The line is: "I am unable to control my wanking"
oh, and pics or it didn't happen