Does make me wonder how often the libido of a character comes up in play for most characters/groups?
4/11 of my most recent characters.
2 male:
* (5e) My 1/2elf ranger in SKT - Had a fling with an NPC fm human mage in a town they were defending. Then, while working the diplomacy angle, charmed (non-magic) one of the Storm Giant princesses & they found new uses for enlarge/reduce person spells. And then on a gambling boat he & our fm human cleric (fellow PC) had way too much to drink, missed a planned ambush, and the rest of the party found them in a compromising position in bed the next morning....
* (PF game) My Human Wizard/Bard & another PC, a Human FM Barbarian/Cleric, hit it off. Actually she seduced him. They married under her clans customs. At first they was adventuring for the hell of it. Now they save the world etc for their twin toddlers & an unborn 3rd child.
2 Female:
* (PF game) My Lawful Evil FM Tiefling Wizard has a thing for LG male Paladins.... She's drawn to them like a moth to flame. Ideally PC paladins, but NPCs will do as well.

Specifically I made the character to play off of our groups paladin. The guy plays really awful paladins. Always has. He's just no good at it RP wise. And the DM for that campaign didn't feel up to challenging him on that front. So the pair of characters I made, I made specifically to push his buttons in various ways & get some improved RP out of him.
And I know the AP we were playing, so I was also trying to get him used to dealing with evil sorts in ways other than just "Paladin Smite!" as there's a key chapter where you need to redeem a succubus & shift her alignment from evil....
He could practice for this by trying to redeem my vaguely evil characters. Or at least the seeds of this idea could be planted in his head. The tiefling never did manage to actually seduce the PC Paladin (though she did bed a few NPC Paladins throughout the AP), but my efforts to improve the other players RP were successful.
* (5e) Hmm, how to keep this PG13 enough.... My FM 1/2ling barbarian is an adventurer (and a barbarian!) specifically because of poor judgment concerning her curiosity of a satyr party/orgy she snuck into. She didn't initially
intend to participate, just see what all the fuss was about. But with enough booze, drugs, & pheromones, things spiraled out of control. And so although she had a good time (at least what she can remember) she's now far from home, has had to learn to fight, and is beginning to suspect she might be expecting....
{this character started out as an NPC, in a much more mature rated game, where some of the PCs did attend this party. Then they set off to rescue her from the satyrs & made things worse via a Cubic Gate....}