Sex and romance are a big part of Baldur's Gate 3. You can choose whether or not to display nudity during the cinematic, whether or not genitalia are visible, and whether or not to share what your character does with nude, visible genitalia with your co-op party.

You can make any conversation scene private in co-op by clicking on the box in the lower left corner of the screen, and that box is checked by default to "Private Moments" If you are not shy about engaging with NPCs, you can use the options menu to select "Private Share Moments" can be checked. That way, regardless of what your character is doing, the privacy option will remain unchecked by default and even your dreams (which in my experience have not been sexy) will be shared.

Unfortunately, as stated in the Baldur's Gate 3 co-op guide, it is not possible to initiate a romantic scene between two co-op players.

"Our romance system is designed only for romancing NPCs. However, if you and your co-op partner kiss the monitor at the same time, a shock of static electricity will produce a heart-pounding effect similar to the sensation of love."

Larian said, "In some cases, you can have a polyamorous relationship," but it is not clear if this is a relationship between multiple players and one NPC, or if the companion prefers to be exclusive in that regard. Mind flayer parasitism in the brain is just one of the problems faced in Baldur's Gate 3.

If you were reading this on release day: Baldur's Gate 3 is very interesting. Personally, I'm enjoying it despite the bugs that come with Larian's massive sandbox.