An underage person who is overweight; portmanteau of jailbait and whale. Jail-whales may or may not come equipped with a whale tail.
"This girl I met on myspace sounds really cute but she's probably a jail-whale so I'm gonna steer clear."
by Ailurus January 20, 2010
The most endangered form of whales, which are also highly delicious when in the form of cake.
Mmmmm, I could really go for come jailwhale right now.
by M Geezy25 October 27, 2008