thwappin' 

Having sex.

They be thwappin' in the other room!

thwappin' by Slooperz August 11, 2010

thrappin 

1) to masterbate quickly to relise built up pressure of the gunk sack.

2) to pleasure yourself over a smutty mag/film/thought/smell/idea/10 minute freeview on adult channel/trevor mcdonald/small animals/clothes pegs/the girl who gets changed by the window at number 34.

..do much week end brett...? na buh, spent the mornin thrappin like a gud un then ate some marmalade..

thrappin by hairy berry September 11, 2006

Thwapping 

When a guy pulls his dick out when receiving a blowjob and slaps it against the other persons tongue or face.

Not sure how to give an example of Thwapping :/.

Thwapping by Mr_Fabulous April 27, 2014

Twappin Line 

When man slaps his semi hard penis on the extended tongue of woman.

Steve had to twappin line on Barbra until he got fully erect.

Twappin Line by anonymous April 19, 2018