The masculine term (m) that refers to a person who engages in oral stimulation of another male's penis.
The more technical term for a person who performs oral sex.
Other common terms are: Icing Expert, Icing Queen, Cock Sucker, Dick Licker, Head Eater, Dick Lover, Cum Eater, Bone Gobbler.
The person receiving the blow job, obviously a male, is technically referred to as the 'fellatrant' or 'fellatee'.
Another feminine term is Fellatrice, which refers to a female being the one performing fellatio on a male.