When I was with my now ex wife it happened for me, 1 of her friends who we used to see a lot on nights out really took my eye, 10 years my younger at the time she was 23, blonde petite size 8 and lovely pair on her, anyway when I got to know her better I started to flirt with her (never in front of anyone), I used to show her my tongue and say "i would love to go down on you and give you multiple orgasms", this used to become a thing with us and one night I said to her that I was that desperate to go down on her that I would give her 100 quid if she let me, this again became the common joke, me saying things like "if your ever skint don't forget I will give you 100 to go down on you", a few months passed by and every time I saw her I always reminded her of the offer and although it was sort of just a joke/flirt thing going on I really did want it to happen, then 1 day when she knew I was alone I got a tex message that simply said "Have you still got that 100 quid? xxx" We planned it and it happened, only once, we did everything and it was amazing, she was single at the time and is now a single mother, I still see her out and about and I often look at her fb profile and have to say ive got off over her photos and the memory of that day, after the event occurred we carried on as normal as though nothing ever happened, but it did and it was very good, so it can happen, its just how to go about it.