One summer after dating my gf for two years I was at the local lake doing some sailing on 16ft Hobie cat sailboat. My gf now wifes sister was also there with a friend and friends daughter. The sun was out and it was hot. During the course of the afternoon while laying in the sun with the girls the friend and her duaghter would leave to look around the area and explore. During that time I would chat with my gf sister now sister in law. After a while I ended up applying some suntan lotion on her and eventually got to apply it to her beautiful muscular thighs. At first it was not too high on her leg but with each other stroke of the lotion I made it closer and closer toward her beautiful pussy hidden by the blue Lycra material of her bathing suite. She lay back during all this with eyes closed and just made the slightest noise of pleasure which imboldened me to continue what I was doing. Because I had no idea when the others would return I could not dip my fingers under the hemmed side of her suite and work on her little love bud and juicy pussy lips. I could only think to rub on the skin of her thigh enough to make her labia to open and close repeatedly stimulating her pussy and clitoruos simultaneously. This had the desired affect as I began to notice beds of sweat beginning to form on her face with eyes still closed. I also noticed a line of moisture starting to expose the line Of her slit.