Originally Posted by wordisbond
I think to pull of the inside slip/left hook you also gotta commit to the slip (if that makes sense). You are gonna temporarily put yourself in the line of fire (for his right hand) so you gotta make the slip as quick and tight as possible. You gotta also put yourself in range to land the left hook so you might also have to move forward/to the left when you make your initial slip.
The thing about his right hand...This is why the timing is crucial, because he can't hit you with his right hand (in any meaningful way) until his left hand comes back. So you slip the jab as it is coming to you, not when it gets to you. And when you slip, you slip the length of the punch, not the end of it. If that makes any sense.