After care for both of you needs to be in there, its really important that you make time for that.
As far as fantasies go and discovering what you like, theres a Kink or Not My Kink thread that may give you some ideas but also look up Carnal calibration in your serach engine, its a test with different levels beginner, intermediate and advanced. Its a good way to see what each other is in to, you can choose to only show the answers that you both say yes to or show everything. It can help.
Be aware of each others non verbal safewords, because sometimes you can’t speak whether because you’re gagged or overwhelmed.
When I’m getting close to not being able to take much more boob slapping and pain, I put my hands on his arms, he knows to end it soon or switch it up.