The Witcher, as a franchise, has explored many different mature themes including sexual content in The Witcher 2: Assassins of Kings available on console and PC, but the next adventure subtitled Wild Hunt has apparently 16 hours of data pertaining to in-game sexual activity.
The Guardian reports the statistic and classifies the data as "motion capture data" meaning someone got paid to put on a suit covered in ping-pong balls, do a bunch of strange nasty, and then go home to beat it furiously. This tweet from CD Projekt Red Quest Designer Nikolas Kolm offers clarification that in-game sex acts took 16 hours to record and that gamers should not specifically expect to get down and dirty for 16 hours in-game.
Senior Game Designer Damien Monnier offered his thoughts on his company's decidedly M-rated The Witcher 3: Wild Hunt:
We are establishing that your character was intimate with this woman recently in order to plant in your mind, that, at the very least, he must enjoy her company. Through sex we have shown that this is a person who Geralt would be compelled to chase after if she went missing. We couldn't just tell you to go find someone you don't know or care about. It wouldn't work.
When asked if sexual activity was being used in the game's opening cutscene just to sell the game, Monnier was quick to deflect that line of dialog. "No, no, no…" Monnier said. "Sex is the quickest way in which to establish the relationship and provide a justification for the player to pursue this woman."
And now I'm ready to pass a sex-ed exam. Sex is the reason to pursue someone! Monnier continued to offer basis for how sex altered a player's understanding of an objective in-game:
We tell the player that Geralt's lover Yennefer was recently seen in the area and that you should look for clues. This framing gives the player permission to take on other quests while still feeling a vague pressure to continue the search. It's a writing challenge that is almost unique to video games.
I can't say that virtual sexual activity may actually motivate players, but if it got someone a job dry-humping under red lights not decorating dark street corners, great.