When a male slides his genitalia across a woman's upper lip, leaving a perfect shape of semen resembling a moustache. This sex act is named after its creator K-MOOSE.
"Yo man, that girl straight up got a MOOOSE-TACHE mang!" "He busted a MO)OSE-TACHE on that freak homie!" "On the real, she loved it when I gave her a MOOOSE-TACHE!"
by KMOS September 29, 2008