A final, uncompromising demand for anal intercourse issued by a boyfriend or girlfriend to a boyfriend or girlfriend, the rejection of which leads to a severance of relations.
Boyfriend: "It has been three years and alls I wants is to snake on up there. In and out. Real quick like."
Girlfriend: "There is no way I am letting you ass fuck me. Fuck your own ass or shit on your hand and whack off!"
Boyfriend: "I didn't want it to have to come to this but you have left me no alternative. I am issuing you an ultimanal - either we have anal sex or it is over."