Afternoon display

I returned just after dinner and Claire was still there. Amy helped me setup the vacuum and left. I started the job and after a minute or two Amy came back out. “You’re not going to stay in the sun with your shirt on. You’ll have a weird tan line. I’ll help you with the sun cream.” I took off my shirt and she put some lotion on my back. I thought she would give me the bottle but next she did my chest. I enjoyed the touch and saw Claire watching us through the patio door. “Oops, I’m sorry. I got a little carried away. Here, you can finish yourself.” She gave me the bottle and went back inside with Claire. I finish putting on the sun cream and started vacuuming. About 5 to 10 minutes later both girls came back out. They both had change into swimsuit. Claire was wearing a small yellow bikini and Amy was wearing an even smaller black bikini.
“Could you bring the sun cream lotion please?” I picked up the bottle and went to them, admiring their bodies while they installed towel on sun chairs. “Since I did your back, would you do mine?” Of course I accepted. “Do all the back please.” She lay down on the stomach and I saw that her bottom was almost a thong bikini with strings on each sides. I decided to start at her feet and move up. Her legs were very firm and muscular with all her running and I maybe spent more time than necessary on her ass. I did her back and she told me to untie the string of her top, which I did. I took the opportunity to massage her arms and shoulder while putting on the cream and also undid the string at her neck without being asked.
She said thank you and I started to get up when Claire said: “My turn!” I had almost forgotten she was there and I think she saw the bulge in my short as I turned toward her. She was also on her stomach but she had a regular bikini bottom. She was still very sexy and I was very happy to apply lotion to her gorgeous body. To my surprised she told me to unclip her top when I got to her back. She passed it over her head and I manage to get a glimpse of her breast. She dropped it beside the chair and I continued to apply the cream while massaging her. Since her breasts are bigger, she spilled a bit and I managed to rub the side of her breast while doing each side of her back. She said thank you when I was done and, since I didn’t know what else to do, went back to vacuuming with my hard on.
When I was done, I stored all the vacuuming equipment. The sight of both girls sunbathing was really getting me hornier. I had to do something but what?