A penislicker is one who licks penis] on a regular basis, or one who enjoys such activity immensely.
NATHAN: John, you're such a fucking penislicker.
JOHN: Go to hell Nathan.
some one who licks a pedestrians penis in secret, trying to remain unnoticed while still enjoying the taste of the strangers penis.
Dude i was standing on the sidewalk and waiting for the bus, when i noticed a penislicker on my dick!