coupon, n. — Green’s Dictionary of Slang

coupon n.

(Scot.) the face; thus fill in (someone’s) coupon, to hit in the face, esp. with a weapon.

1994		I. Welsh ‘A Smart Cunt’ in Acid House 219: Veitchy [...] draws glasses and a Hitler moustache on Ronnie’s coupon.
2000		T. Udo Vatican Bloodbath 35: You just shut it ya English cunt or ah’ll slice yer fuckin’ coupon open fur ye!
2012		(con. 1980s) I. Welsh Skagboys 18: The arrogant, hate-filled faces: so different tae the beaming coupons that greeted us.
2018		I. Welsh Dead Man’s Trousers 12: [E]njoying the incredulity on my coupon.

void coupon (n.)

(US teen) a nullity, an unimportant individual.

1943

N. Pepper in Indianapolis Star 12 Dec. pt 4 22/6: Voic Coupon — A drippy person.

cash in one’s coupons (v.)

(US) to die.

1957

(con. WWII) ‘Weldon Hill’ Onionhead (1958) 52: I can’t die yet [...] Before I cash in my coupons I have got to sleep with a total of six women first.