to thwackit is to jackoff, spank the monkey, flonk the dolphin, rope the poney, wrestle with the snake, choke the chicken etc. etc.
jimmy thwacked it all night until his shlong turned chrimsen.
to hit hard and percise. Usualy producing a THWACK sound.
With a "THWACK" the bamboo rod hit table.
hero's move in smash that can insta kill anyone
Jack: i have reverse card try and beat me bob
Bob: (thinking emoji) Thwack
to be speed up as much as possible off of speed/meth
lets get all thwacked out, go to the titty bar and rub tuna on ourselfs then go home to our women...
To receive a hand job or blow job, and to not finish.
"Dude, she was thwacking me for an hour yesterday."
"How did you not finish bro?
To firmly slap ones penis across another persons face i.e. to be either very manly or very homosexual.
"Dude! That little limp wristed faggot just thwacked me!"
One jock buddy says to another...
"WHOA! Billy's asleep, someone thwack him!"