A way of intercourse in which the man fucks the girl hard, pulls out, keeps rubbing and cums all over her (like a musket), proceeds to moterboat her tits and gives her a raspberry before jumping up and running out of the room. Often performed by people who wear fedoras.
Hey bro, how did your date last night go?
Great man. I three musketeered her!
Hey, did you see Becky last night? She got three musketeered and came home crying.