Not my real name, just to protect anonymity...but anyway, more MMF than MF.
During my first year in college, I was roomed with a guy who was actually a lot like me and we got along almost instantly. The one thing that I had to get used to was how he would get on his webcam with his girlfriend and they would masturbate together openly. He told me up front that it was going to happen and I told him it was no big deal, I have two older brothers so seeing or hearing someone masturbate was nothing new, but what I didn't know was how often it was going to be. Almost every day, sometimes morning and night, I would either walk in or be laying in my bunk and he would be at his computer, stripped naked and typing and stroking. I have to admit though, it did get me horny and many nights when he was done and shut everything down, I would strip off my boxers and masturbate, and there was no way he didn't know I was doing it since he slept right under me.
This all went on for a couple months until one particular night. I came back from my shower and was in my bed looking at a magazine when he got on and started doing his thing after 15-20 minutes. I let him go on but not too long afterwards he stood up and walked over to the bunks. He asked me what I was doing and told him I was just reading, but what he said after that really caught me off guard.
"Come down here with me."
"My girl wants to see you masturbate too."
"She said it would be hot to see me masturbating with another guy."
"Are you serious?"
"Yeah, don't worry she's naked too so it's not just us."
"Do we have to touch each others' dicks?"
"Beats me, she didn't say exactly."
"And you want to do this?"
"Sure, it sounds pretty exciting to me, so you in?"
"...uh...OK, I'll do it."
"Cool, take your boxers off and come sit by me."
Nervous as can be, I slipped them off and climbed down, naked in front of his camera for the first time. When I sat by him I could tell that she was happy, and sure enough there she sat, completely naked except her glasses. She waved to me and I waved back, and she asked if I ever saw them. I told her that I saw her boyfriend masturbate almost every day. She laughed and asked if I liked it, I shrugged and said I got used to it. She then asked me how big mine was, and I told her around six inches. She said that's about what his is and she wants us to compare them so I needed to get it up. Since I was so nervous it was hard (no pun intended), but I started playing with it and eventually it started growing and made it to it's full length. She had us both stand up face to face holding them straight up, and she nodded and said they looked about the same. We then sat back down and she wanted us to start masturbating so we started stroking and she grabbed her vibrator, put her feet on the desk and started sliding it in and out of herself. They started typing dirty back and forth, and I kept going back and forth looking at him and the screen, and I saw that he was doing the same. 10 minutes went by and then she told him the one thing I wasn't sure about: "grab his dick and make him cum." He asked me if I was ready and I wasn't exactly, but I figured it's gone this far so what the hell. I told him to go ahead and put my hands behind my head and he grabbed my penis and started stroking it. It felt so weird having another guy masturbate me, but he knew what he was doing and it actually felt really good. I told him I wasn't going to last much longer so he told her to get ready so she scooted closer and stared at the screen, and a few seconds later a big, thick line of cum shot from my cock onto the desk and eventually rolled down onto his hand. He kept stroking until every drop was squeezed out, then grabbed a tissue and wiped off his hand. She then said it was my turn and motioned for me to grab his. I kind of lost my edge since I came, but it was only fair so I spun around and grabbed him with my right hand and went to town on it. His head was thrown back and he started moaning, telling me how good it felt. I told him to let me know when he was going to cum and he grunted out an OK. I glanced back and the screen and she was watching the show, rubbing herself slowly. It took a minute or two before he said he was ready, so I pointed it towards him and he blew a nice load onto his chest. A little bit got on my hand, but I got over it and simply wiped it off.
When that part was over he then told her that it was her turn so she scooted back showing us every inch of her front and dug her fingers into her pussy. She didn't stop after one, and kept fingering herself until she was shaking in her chair, toes gripping onto the edge of the desk. When she was done her hair was a mess but we all sat there for a while chatting, but we noticed that it was about 1:30 in the morning and we had classes in a few hours and had to go. We said our goodbyes to her and she said we had to do it again soon, and we both agreed we would. He shut the cam off and the computer along with it, and we crawled into our bunks still naked. We laid there for a minute and he asked me if I had fun, and I had to admit, it was fun masturbating with them and he asked if I was weirded out jacking him off and I said not really, and he said the same. It got quiet and I started falling asleep, but then I heard him moving around and the distinct sounds of him masturbating again. This got me horny all over again so I started stroking along with him, taking about 15 minutes to cum, but that time I didn't even bother trying to clean it up. I just pulled up my sheets and rolled over, letting it go wherever.
That was the first time I ever masturbated with someone else, but it wasn't exactly the last, and it eventually branched off further with them.