Instant messaging acronym for ‘Put a smile on my face’, the term is assumed to mean “that put a smile on my face”. It is a less cheesy alternative to lol and its variants. Pafomf (Put a frown on my face) also exists as its negation.
Person 1: "james was horrifically drunk n hit on her"
Person 1: "which amused me no end"
Person 2: "pasomf"