Top definition
The time when a boy/girl turns 17 and grows a tail.
"hey Martha, did you see the tail on that guy?"
"oh yeh, he is hot! Did I tell you I was at his seventeenth birthday?".
"Tail is a euphemism btw".
by MQ-N May 11, 2009
Get the mug
Get a seventeenth birthday mug for your mother-in-law Riley.