To administer a hard open-handed slap, usually to the face of a an unfortunate and irritating pest, such as a younger sibling or co-worker
I gave that guy such a poesklap, he saw into next week!
A nasty and very effective smack upside the head. Afrikaans Origin and derived from Poes (vagina) Klap (smack)
Barry needs a PoesKlap