musical tourette's 

An artificial form of tourette syndrome in which the singing or speaking of a line from a song by one individual produces the spontaneous and not entirely voluntary singing or speaking of further lines of said song by another individual. This phenomenon is most often seen among people in good moods.

When you or your friends have musical tourette's, life is like a Broadway musical.

musical tourette's by TheLastPunslinger May 15, 2005

Musical Tourette's 

To randomly break out in song

Tiffany: "Bye Jenna"

Jenna: "Baby bye bye bye.. BYE BYE"

Kevin: "What's wrong with Jenna?"
Tiffany: "oh, she has musical Tourette's"

Musical Tourette's by HarryStyles123 June 25, 2015

musical tourettes 

being unable to control the temptation of suddenly bursting into song

"wtf iz wrong w/you?!?!"
"dude its musical tourettes, i cant help-smack that all on the floor"
"???"
"smack that till u get sore"

musical tourettes by me myself and iiiiii August 19, 2008