Replying to Stomping 360s and starting to put grabs in?

So I have been getting alot better at my 360s.  The last two times I have gone I have had them all day until the end of today.  For some reason at the end of today I kept getting the same problem I had when I first started threes.  I would lean too far back and to the right and would land unbalanced and wash out on my landings. 

Anyways I think I will be able to get my 360s back to normal next time, but now my question is how do I start throwing grabs in there?  I can do a grab behind my boot on 180s and I want to start grabbing my 360s so that my arms don't flail everywhere and I can have more style.  Which grabs should I try and how should I do them.

thanks a ton