This definition is the true definition and the others are misinformed.
Pwank, pwanking, pwanker, pwanked, pwanks.
To pwank or pwanking consists of
masterbation whilst having a poo. The ultimate release. Both the prostate and the penis are stimulated
simultaneously so that
ejaculation is highly likely. This act lasts a matter of a few minutes, any longer than 10 minutes and it tends to arouse suspicion amongst your peers.
The origin of this term is unknown, but can be seen in popular literature as early as 1998.
John was in
the bathroom pwanking for so long that I had to slash
in the garden.
I couldn't pwank at someone else's house- it's just not right.
Your
girlfriend loved watching me pwank- she's nasty mate