noun - A very sexually attractive person, object or idea.
Jake: 'That bird is well fit.'
Toby: 'You're not wrong there - she's jumbo tonk.'
or
Jake: 'Whoa dude, don't tell me you managed to slam the new jumbo tonk hairdresser from downstairs?'
Toby: 'Let's just say, "She got her's - for sho.'"