(adj) Had sex with a MILF
Hey dude, look over here! This naked MILF you see before you is totally getting banged by me and my sausage! I'm totally getting milfed!
To be beaten or badly affected by an event, can replace the word 0wned or nerfed etc.
'Man we absolutely milfed those n00bs'
'oh dude, we just got milfed by the other team'