Ooh, it certainly does sound like you have a start! Does she know you like her pinching you? Do you ever say, Oh wow, yes that's nice, do it harder, thank you, type thing? As long as she knows you are enjoying it, she will be more at ease with allowing her own nature out, I think.

And what about you - do you as a sub desire to please/serve her in different ways - massaging her, licking her feet, getting her to lie back and just enjoy the pleasure of letting you please her? So that the pleasure/activity gain is not just obviously yours, with butt play etc?