Viagra? No, for a sixway we get prime MC who can fuck girls all night long, not limp dick MC who can't even handle both Mel and Sarah anymore (I'm still bitter)
Impregnation fest
All night? I'm having them fuck a whole week. Whichever break from school fits the timing, they spend at Bella's. They take breaks for eating, sleeping and the bathroom, but otherwise fucking is constant. The only time the girls put on anything more than a bathrobe or sexy underwear is when a couple of them have to make a trip to the store to restock on supplies.
Pornworld Super Viagra. "You'll fill all the holes, even the ones in plot."
As for the... Isage? SaBe? Whatever. The best I can do is to first speculate a bit on Bella's secret room. I'll start with the assumption that it is a room where Bella keeps important possessions that remind her of painful things she doesn't want to forget but can't bear to look at on a daily basis. For the sake of plot convenience she forgot to lock the door after the last time she needed to think of the past. Among the items is a crib that Bella and James bought when Bella was pregnant. She miscarried or in some other way lost the baby and that was a big part of what soured the marriage until James finally disappeared.
Family issues are a pretty big deal for just about everyone in this game, but Bella's issue is in the other direction. Everyone else has issues with their parents, Bella was robbed of her chance to be a parent. The revelation leads to some bonding between Bella and the girls. It's painful at first, but eventually they get more relaxed.
From this shift in their relationship you can build among other things a series of slightly drunken competitions that eventually lead to Sage boasting about sex skills and the challenge can only be resolved via threesome. It's better than "they get drunk and fuck as a result of a bet", but still really crude. It might get better with more groundwork in how Bella's and Sage's relationship evolves, but that's pretty much begging for disappointment when new canon contradicts it.