What's the difference between a back tuck and backflip?

Question

other than in a tuck your brick your knees all the way up and separate them

Answer 1

What's this question have to do with bicycles? Being from a diving background, I'd say that a tuck is one of several possible positions for doing back flips, or flips in any other direction; and that separating the knees is frowned upon.

Answer 2

Don't know why your asking about gymnastics in cycling.