Literally a sexual boy toy who belongs to an older man. The younger guy is a bottom or anal receiver while the older guy is the pitcher, or top. Also, an extremely submissive and ass-kissing employee or student.
Who's the tasty twink over there by the bar? Oh that's the bartender's new butt boy.
Hey guys, I got an A+ in History. No wonder, you are such the teacher's butt boy!
Used in West Indies to refer to someone who is either a homosexual, or is suspected of being a homosexual. Usually is an insult. This is of course a very dangerous situation. See also batti boy and chi chi man. There are many more names. If you are still confused, listen to an Elephant Man CD.