Wife Friend Sarah

My wife has a friend that has come to several of our events plus vacation. She is a married woman who has a husband and two kids, and they have gone on several vacations with our family. There is something about her that drives me crazy. She is just a plain Jane girl that makes me hard when I am around her. When we were at the beach, her top was a little loose enough to see her nipples. She kept doing it every time I checked her out. One day when I had to work, and they stayed in bed, I noticed her bikini bottoms lying on the counter drying, so I took them into the bathroom and jerked off in the area where her pussy would be. I want to fuck her so much I can't take much more. I am working it up to still her panties. When I go back around her, I can't wait.