To
Retire,
settle down.
It's based on the idea of an old
gun slinger who finds true love and 'hangs up his guns' to become a farmer.
In modern usage, it could be said about a guy who has previously had lots of casual relationships, or considers himself a 'playa'
"I tell
ya man this chick is sooo sweet!"
"So you gonna
hang up the guns?"
"Holstering my weapon as we speak"
"
Mug!"
