Do it with massage oils.
Do it with porn playing.
Do it in front of a mirror.
Don't do it for a week and unleash yourselves.
(or do all 4 at the same time)
Those 4 really lit a fire in our sex life.
A little farfetched, but... threesome?
Talk to her about it, it might be something she wouldn't mind trying.
I did, and I got to the point where I was in bed with both girls... but my girlfriend got too freaked out last minute and we ended up bailing. Holy fawk was that awkward.
Maybe you'll have better luck.
Also. Not sure about your fitness situation.. But when I got shredded after doing a couple rounds of p90x, she couldn't keep her hands off of me. She would want to do it in the car, in a mall washroom, in the park, in my office, etc etc.
Some things to think about. Happy nailing