You don’t need to go fast, you can be caring and very gentle with your touch.
See it as any other form of massage as if you were massaging his body.
You can start very gently and explore his limits and then keep him at the 80% excitement level.
Honestly, the only way to learn is to try and practice.
It’s something which is very natural to do and I am sure that you’re already very good at it. 😉