I'm not sure how taboo this really is, but it is a current fantasy of mine.
A while back, I watched a video where a young woman wearing nothing but panties stood in front of a guy while he jacked off. When he was ready to cum, she pulled her panties away from her body and had him blow his load down them. When he was empty, she let the band of the panties snap back and rubbed the front, coating herself and the panties with his cum then said she planned to wear them the rest of the day.
A few years ago, I told a fuckbuddy about the slight panty fetish that I have. She wanted to see it in action so one morning before she went to work, I straddled her as if I was gonna titty-fuck her but instead I jerked off with a pair of her clean panties and then shot in them. She put them on and wore them to work that day. Got her so worked up that she had to come to my place on her lunch hour to fuck.