Charlotte Crosby from Geordie Shore apparently pee's herself when tickled. About 3/4s of the way down
http://www.cleo.co.nz/celebrity/celebrity-stories/2015/3/charlotte-crosby-the-cleo-interview/
http://www.cleo.co.nz/celebrity/celebrity-stories/2015/3/charlotte-crosby-the-cleo-interview/