Hi. I hope you won't ignore this because since This is going to be about CHEATING. Idk if this violates Rule 1 but hope i get some feedback

I know it's morally wrong, and unfair but i just want your opinion on how to escalate things.

So a little backgroud. I(m) have a partner, my (f) friend has partner. Apparently, her partner looks just like me and she always teases me about it saying that I am her school boyfriend. I kinda like her too, tbh. She's flirty and touchy. So i reciprocated that energy and i always touch her too. On her back, waist, inner thighs, sometimes climbing extremely close to her crotch. Sometimes touching her crotch. She yells at me saying it's touching her privates but doesn't push me away or tells me to stop. I always carress her thighs whenever im beside her. Most of the time she puts her leg over my thigh and lets it hang. She sometimes kisses me on the cheek jokingly. One time, she kissed me i said "not on the lips?" She replied " there are too many people here. Next time when it's only us "

Now this friend of mine is coming over because she's going to help me with something. She's going to sleep overnight at my house. How do i escalate things?