Keeping in mind eighteen is "legal," that's technically a teenager... For a while, during the time I served on adjunct faculty at a nearby university, I recruited and procured young college-age men for KK - teenagers in some cases. Each encounter was fascinating, a somewhat reluctant, but simultaneously enthusiastic young man, paired with my experienced, depraved wife.
The fucking was always amazing - a young man with stamina, a short refractory period, and the ability to serve up hard cock, and big loads for my cum-slut wife over an entire evening... few things hotter than being awakened in the wee hours of the morning, to find your hot wife riding a young guy's hard cock, the two of them in bed next to you, as she's fucking herself senseless on his throbbing dick...