I suppose it depends on the friend and your wife/gf. I have posted this experience before on here.
my ex wife had a empathetic crush on our soon to be best man. She said it would be hot if she fucked him first after we got married before I had her. I thought about it for a couple of days and the more I thought about it, the more horny it sounded so we concocted a plan for her to fuck him directly after the wedding.
He is a very shy, nice guy but not very attractive. As kids of 14-15 we played doctors and nurses with a local girl so I knew he had a big cock. Anyway the wedding came, our vows taken and after the church we all went to a very local venue ( literally across the road from our apartment) i suggested she went to our home with Ian to get changed while I greeted the guests coming in for the night reception. As they got in (Ian was totally unaware) she asked him to help take off her gown and he was very eager to help. As the gown came off she was in white silk sussies, stocking, panties and matching bra. She said his mouth was open wide as he gasped "you look as sexy as fuck, he is in for a great night tonight" jen thanked him and with a glint in her eye pulled a prepared camera out of a drawer and asked him to take photos of her in her wedding underwear. He nodded, took the camera and started snapping away as she did some poses. She could see his bulge so she started stripping. First the bra then the stocking and sussies then finally her panties. she had put her heels back on and his bulge had become a wet patch so she walked over and pulled his zip down and his fat cock jumped out at her. "Let me help you with that" he did not resist. She said it was at least 9" long and nearly as thick as a coke can, it had grown since we were kids. She said his cock was very sticky with precum and was running down his balls so it took a while to clean up. They moved to the bed and got into a 69, she told me he cut twice before she climbed on top of him. They fucked for ages and i must admit they were gone for nearly 3 hours and by that time the guests were wondering were my new wife was. I told them she had been up all night and she had gone to bed for a while, well I wasn't lying. Ian came back and was avoiding me at first then she came in looking radiant and smelling of sex. I went over to Ian and told he I knew all about it and help plan it after that he was fine and continued to fuck with jen on many occasions both with and without me (and a few times with some of his friends too).