Need Advice pls.
Have been seeing my gf a couple of years and our sex life is healthy but her teen daughter kinda flirts with me. She sometimes comes into the bedroom when I'm changing and stares at my crotch, commenting on how many buttons I have on the fly or says "look at your sausage sticking out" when she can see the outline through my shorts.
She like having a back and shoulder massage as well as running my fingers down the back of her arms as it tickles her and gives her goosebumps. She pretty much likes gentle "tickles"/strokes anywhere on her shoulders, collar bone, back of her legs etc. So over the months theres been a few incidents. She's had on short sleeping shorts and one weekend morning we sat on sofa together, she was curled up with her bum facing towards me and I spent ages stroking the back of her legs, right up the top of her thighs and even across the bottom of her exposed bum cheeks. She liked it but never says much other than "it tickles" and she squirms and giggles. Also she doesn't wear a bra in bed, the other day I came home from work and she'd been home all day ill. When I sat with her, she put pillow on my lap and laid back on it playing on her iPad, knees bent up and I was stroking her head, tickling her arms and also just above the hip bone where its sensitive. Pretty much all round her exposed midriff, running my hands along and up her rib cage and I was literally about an inch from the base of her breasts!! My heart was pounding, I could see her breathing was increased but she just lay calmly lapping up the attention. When I ran my fingers along the waistband of her pyjama bottoms, due to her slightly curled position and being long-legged but short body and having her knees bent right up, her crotch was only about 6 inches from my fingers. I didn't know whether she was just waiting to see what happened or what. Another weekend morning we did a similar thing but she lay on one side with her face inches from my cock! Back in summer she put her hand almost right in my lap so I could tickle the back of her arm and she kept twisting it about so I could tickle all of it but the base of her thumb kept touching my cock which then got harder. Next thing I know, rather than putting her head in my lap with a cushion as normal, she just plonked her head down right on my growing erection!! I didn't know what to do or say and her mum was in the house this time so stayed quiet.
Another time she asked for a proper back massage so got her to lay on my bed, again on a weekend morning, small vest and shorts, no bra and I spent ages doing the same, running my hands over this tall slim, pretty blonde girl with a bubble butt!
One night in bed she got in to give her mum a rare cuddle (shes too old for all that really), I got in behind her and she shoved her bum right back in my lap and I know she could feel all my package! I only had thin boxers on and my cock started to grow so I twisted away slightly cos she's cheeky I thought she might call out "whats your sausage doing pressing against me" or similar cos she thinks saying things like that in front of her mum is funny. After I twisted my cock away, she moved her bum about, not sure if she was trying to find it!! Me and her mum are pretty open and they both know I'm comfortable with nudity so her mum trusts me around her, luckily.
On another occasion I'd been in the shower and was stood in the bath still drying off and her mum called up to me from downstairs so I opened the bathroom door to shout back, the step daughter was in her room and knew I'd just been in the shower and without asking or knocking on the open door just walked into the bathroom! My towel I think was just covering my cock but I don't know. We all just laughed it off. Unfortunately the hand in lap or looking at my crotch while I'm changing hasn't happened for a while.
Really don't know what to do, she's gorgeous and its a massive thrill stroking her body and being inches from her bare breasts while she lays happily on my lap. How would you guys take it from here? On one hand she prob wants something to happen but its seriously taboo, on the other, she may just enjoy the attention.

Jacking off to the pics on my daughters phone.

would anyone rip my daughters bikini off of her and fuck her ?