You can do a block string pressure and cancel into Aura then do another block string or 50/50 or grab. Gives you a little bit more chip damage or a setup and it is deceptively fast for people to react at first. You can go into Aura after ending a combo for example Slide. It will give you more Aura time from when the opponent gets up and it should be safe.
I'm more in favor of using it after the combo to be honest, normally you get plenty of time after a slide or similar knockdowns and using it mid-combo means that you're losing active seconds as the opponent can't hit you anyway during the combo.