When your erection is only semi, it does not go all the way. This is actually more embaressing than a true boner because people think you 'cannot get it up'
HAHHAHAHA LOOK PHIL HAS A SEMI BONER OVER CHARLOTTE!
ITS PROBABLY OVER JOHNNY CAUSE ONLY HOMOS GET SEMI BONERS!
By Rafa
Semi-boner
When ones penis is no longer erect, possibly either after blowing ones load, or just losing an erection. A semi-boner is often used for playfully slapping ones friends in the face while they sleep for a hilariouslygood time.