"Hey Jim!" my sister, Jen, called to me from downstairs. "Come lay out at the pool with me and Meg!"
"OK" I called back
I got changed into my bathing suit and headed downstairs and outside to the pool. I sat down on a lounge chair next to Jen and her friend Meg and greeted them. Jen and Meg were both 20 and beautiful, while I was 18. Meg was already lying down in her small, sexy bikini. Jen was was standing, checking her phone as I got there. When she finished, she put it down and began to pull off her cute white sundress.
For the past year or two, I found myself very attracted to my sister, even masturbating to her at times. So when I saw her stripping down into her bikini, of course I stared. Her bikini top was very small and tight, showing off her very nicely shaped breasts. Her bottom was also very tight and had a very low line, so I focused my staring on her pussy.
"What are you looking at?" Meg asked.
SHIT! She caught me! "Hmmmm?" I responded, trying to play it off as if I didn't know what she meant.
"What are you staring at?" she repeated. By this time, Jen had finished taking off her sundress and sat down.
"What do you mean?" I asked.
"You were staring at your sister's pussy!"
"No I wasn't!"
"Yes you were!"
"No, I swear!"
"Admit it! You were staring at your own sister's pussy! You think she's sexy and would do anything to fuck her!"
"That's not-"
"ADMIT IT!" she cut me off.
I looked down in shame, knowing she was right and quietly said "I admit it. I was staring at my sister's pussy. I think she's sexy and would do anything to fuck her."
She started laughing while Jen blushed a little, before trying to laugh it off.
"You dirty bastard," said Meg. Jen leaned over and started whispering into Meg's ear. She let out an evil laugh and they started to converse in whispers for about a minute. I was feeling a very strong mix of shame and terror at what was going to come. They both got up. Meg said "Stay right here" and they went inside. A couple of minutes later, Meg came back carrying a bag of clothes.
"We're going to make you eat those words," she said. "Now get undressed and put these on."
She handed me the bikini my sister was just wearing. I hesitated, so she told me that it wasn't a test and to just do it. So I took off my bathing suit, revealing my cock, which was beginning to harden, but Meg didn't say anything. I first put on the bottom, which didn't completely cover my now-erect cock. Then I put on the top. Meg helped my put stuffing in it to give the appearance of boobs. Then she handed me my sister's sundress and had me put it on as well, so I did. Then she gave me a wig of girl hair. I put that on and she mockingly told me I looked beautiful. She then put a blindfold on me and I heard the snap of her phone camera as she exclaimed "Beautiful!"
"You can take the blindfold off now," Meg instructed me. She showed me the picture and I was a little turned on in a weird way. "Here's how this works: Once you put that blindfold back on, you CANNOT take it off again until you are told. Otherwise, I will let the picture out and ruin your life. Understood?" I nodded. "Good! Now let's go inside." I followed her into the house and up the stairs. We stopped in front of my sister's closed door and she ordered the blindfold back on and reminded me of the rule. I put it on and we guided me into Jen's room.
I could hear my sister whistle when she saw me. Meg guided me onto my knees. Jen then said "Mark, this is my brother Jim. He likes to dress like a girl and get fucked like one. Jim, this is Mark. Mark likes his dick to be sucked before fucking anally."
I spoke up and said "I never said that!"
"You said you would do anything to fuck me though. Now, I think you can both see how you can help each other here. Open up Jim!"
"That's not what I-" My cheeks were grabbed and I felt something hitting my lips. I tried to squirm my head away from it for a few seconds until Jen said "Don't be shy!"
At that point, I realized that what was hitting my mouth wasn't flesh, it was rubber. Also, based on where my sister was speaking from, it must have belonged to her. It must have been a strapon! I decided then that I would do anything to fuck my sister and plunged my mouth over her cock.
It filled my entire mouth and I heard her and Meg let out a small cheer. I felt my cock get harder than ever before. I sucked on it for a few moments until Jen pulled it out. I noticed my mouth follow it slightly as she pulled it out. "Easy there, you little slut. You can take off the blindfold now."