The act of grabbing the excess skin of your ball sack, lifting it up like elephant ears and slapping a girl in the face with your dick!
Branham - Thompson, what happen with that chick.
Thompson - She sucked at giving head so I gave her a trunk slap.
Thompson - She sucked at giving head so I gave her a trunk slap.
by ~BTR~ January 21, 2012
When your girlfriend and/or wife is post sex cuddling and you roll over and whack her in the eye with your penis.
by Rezelka August 23, 2012
"I really must wear something more supportive than boxer shorts when I run. My penis is raw from all the trunk slaps. It sounds like two elephants high-fiving when I run downhill."
by fairycakesupprise August 15, 2016