How do grabs work?

[DarkJosh]

I don't really understand why I sometimes can only punch someone a few times In a grab, an also sometimes throw him when I think I'm doing the same thing. And also. Why I throw someone up or to the side

 

[Darklink401]

I don't really understand why I sometimes can only punch someone a few times In a grab, an also sometimes throw him when I think I'm doing the same thing. And also. Why I throw someone up or to the side

If you input A after you grab, you will pummel them.
if you input a direction, your character will throw the opponent in that direction

if your opponent presses buttons quickly, he can escape your grab faster.

 

[Mario & Sonic Guy]

You must also keep note that the grabbed opponent's current damage determines how quickly he/she can break free from your grab. The higher the opponent's damage is, the more pummels you can do before you have to start throwing him/her.