She ask that I joined

“Only if you join me.”
“No problem.” And with that I quickly removed my shorts and threw the rest of my clothes on the ground. She watched me, especially at my mid-section. “Ok you’re turn.” She looked at me a bit horrified. “**** now. Get those hands away for your breast and drop the bikini.”
“I did ask for it.” She became resigned. Took a deep breath and suddenly turned away from me and dropped her bikini bottom. Her ass looked great and I enjoyed the view. Then she turned toward me but she had a hand in front of her pussy and the other arm in front of her breast. She had problem with the arm but it still hid her nipple but because she had good size breast (around D cup), she did spill a bit.
“Hey, you’re hiding.”
“The dare was naked but it didn’t say anything about hiding with your hands. Ok, let’s get this over with.” She turned and looked around to see if someone was there. I looked again at her ass but then had an idea. I started running for the backyard without making sure that we were clear. Fortunately, and because we live in a dead-end, it was clear. I got into the backyard way before her because she still kept her arms in front of her. I grab her bikini top and buddle it in my hand. She reached me and saw that I had her bikini top. “Hey, give it to me!”
“No, you’ll have to come and get it.” I detected that one of her breast had gotten free of her arm in her run. She noticed me looking and glanced down. She quickly turned around and replaced her arm to hide everything before facing me again.
“Please, give it to me.”
“No. I think you cheated by hiding and that’s your punishment. You’ll have to use at least one arm to get your top back.” She abruptly rushed me, reaching for her top with arms. I didn’t have time to ogle her and just turned my back to her in an attempt to keep her top away from her. She jumped on my back and I knew I would soon lose to her if I didn’t do something. I didn’t want to hurt her and I admit that I enjoyed having her naked breast against my back. I did the only thing I could think to do to keep it away from her. I threw it over the fence with the rest of our clothes. She left my back and went to the fence to look through it to see her top.
“Shit! My sister is here. We have to hide. I don’t want her to catch us.” (I later learned that her backdoor was locked because she had come out the front door, thinking that if she wanted she could get back in rapidly. She didn’t think to unlock the backdoor. ) She ran behind the shed. I followed her but realize that the space behind the shed was very limited and I wasn’t sure we’d both fit.