Opposite of the 'Bros before Hoes' rule.
A single guy who chooses to go and hang out with female company or other event attended by women rather than hang out somewhere with his male only friends.
This is done in the hopes of scoring or to put in the legwork so he may pick up a woman at a later time.
So called presumably, because you are out to score some booty
A guy who hangs out with his established girlfriend/wife over his friends doesn't apply and is still pussy whipped