Just thought about this recently but holomems have actually a lot of sexual discussion when they are off-stream
For example when Korone and Marine played puyo tetris Korone asked Marine what she did today and Marine didn't replied and Korone told her something like "You did something you don't want to tell to your fans, right ?" implying masturbation probably
There is also this recent clip when Marine said she talks about things she can't say on streams when she is just with holomems https://youtube.com/watch?v=9GAQsqcYrFg
And there is pic related obviously