1. The very means of slapping someone (or
something) in the
face (or elsewhere) with ones penis. derived from the
sound it makes when contact is made.
1. WHOPACHA! (*screamed whilst performing the act.)
2. That
bitch is gonna
cop a whopacha in the
face!
3. that n00b just got whopacha'd
4. OMGWTFBBQ! i just got whopacha'd