(Disclaimer - With permission and encouragement of my girlfriend, this is me re-telling the stories she has told me. It's a mix of how it started, random memories, and her most recent encounter. Everyone involved is over 18.)
Before we got together my girlfriend had smoked weed for years. She enjoyed a joint most weekends and used the same guy to buy from, a friend of a friend.
When she needed to save money she stopped smoking for a few months but found herself getting stressed without it. She reached out to her supply guy, explaining money was tight, and asked if he could do some kind of deal. He suggested sex for weed. To his surprise, she didn't need any persuading but she negotiated him down to blowjobs instead. Now, this isn't out of nowhere. When they first started hanging out they got stoned together, and she had given him a hand job a few times.
So, for about a year, until she became my girlfriend, she was sucking him off most weeks for a couple of joints worth of weed. This all came out during some dirty talk confessions we had together. Her arrangement with this guy was straight to the point. Most of the time she sucked him off on his sofa. She would sit beside him and lean over or get between his legs on the floor. Sometimes he liked to stand with her on her knees. Occasionally, if she needed a ride somewhere, she would suck him off in his car. On almost all occasions she swallowed his cum, but sometimes he wanted it over her tits or face.
By the time I began dating her, she had built up a small stash of weed so she hadn't seen him in a while. She had also made alternative arrangements to buy from someone else, but it was going to cost her a lot more money.
During dirty talking, she told me how she missed sucking his dick and how naughty it made her feel. She's a very well-presented and innocent-looking girl, people would never guess the things she's been up to. I took a chance and said she could carry on sucking the guy off for weed, so long as she told me all about it. I think she knew I would suggest this as I'd already admitted to doing some cuck stuff in the past. So, now my girlfriend is meeting an old friend once a week to suck him off, with a few added extras, in return for weed for us both.
At the time of writing this, her latest visit began with her stripping off. He's more dominant now, he had her stand in front of him where he sat, his hands feeling all over her body. He slapped her ass a few times while sucking on her nipples. Then he played with her pussy until she was dripping wet before pulling her onto the sofa and finger-fucking her to orgasm. He then got her on her knees so she could worship him. She licked, kissed, and sucked every inch of his cock and balls. He face-fucked her, only stopping to slap his dick on her face, then shoving it back into her mouth. A little time later he told her he wanted to cum. Having sucked him off dozens of times before she knew the exact pace to get him off, a few minutes later he was cumming in her mouth. He's a heavy cummer but this load was a big one even for him. She had every intention of swallowing it all, but he had to pull out of her mouth and give her a few spurts over her face and tits. She cleaned up the best she could and came home to me.