Don't go sideways.
When I do gaps my front wheel doesn't really lower *that* much, its more in the preload of your body than anything.
The kick isn't really a kick as such, its more of alot of pressure on the pedal, rather than a stab. Hard to explain.
Gte right to the edge of the object you're gapping off, push the bike back into the object right on the edge as this helps the tyre compress and get a bit more length.