In short, I want to be her living toy. Sort of a very mild BDSM, but closer to a "free use" relationship.

Whenever she wants anything physical/sexual, she has her way with me. Wherever we are in the house, whatever time it is, however we are dressed. It doesn't need to be sex either. If she wants a warm body to cuddle, I'm there. If she wants someone to bathe her from head to toe in the shower, I will. If she wants only my tongue to bring her off, I do it. If she wants a massage, I am the masseur.

I will likely have a boner during 95% of this but it's entirely up to her if she wants to help with my problem. I certainly hope she will help, but it's still her choice. I am but the toy.