How to Please her while sitting

Hey I(M 19), have a girlfriend. She is a bit conservative and does not let me kiss or do some foreplay on her. She is more into hugs while she sits on my lap. She enjoys while she sits on my lap , close to my dk and she enjoys the hugs. I would like to know how to pleasure her well enough so that she feels like proceeding with everything. What is the best way to turn on a girl who is sitting on top of the dk. Is it about the movement. Humping is done slightly but i believe it is not hitting the right spots. Could someone tell me what to do ??