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!"
After the male has expelled the majority of his semen in what ever manner he deems fit the remaining load is squeezed out along the top lip of the recipient, giving them a creamy mustache like that of a snowman.
Inspired by milk promoting posters typically found on the sides of buses and starring Rupert Grint (Ron Weasley)
"Gave the wife a right snowman's 'tache last night, she looked like she'd been guzzling a pint of milk!"