Originally heard in military units at Fort Ord in 1978. These units were historically named "Buffalo Cav" based in the old west and primarily made of black only troops.
Modern day Cav troopers kept several young ladies of large size and less than attractive demeanor around the barracks in the evenings to "relieve the boredom" and referred to them as "Buffarillos".
"Hey, go down to the dayroom and bring one of the Buffarillos up to our room."
"Did you see the Buffarillo Trooper Smith was with last night?"