HURRAY FOR GAY is absolutely correct! Yay!
Is someone working on writing up a walkthrough for this? The one reason I just can't get into VNs with multiple routes is that I always miss out on crucial steps / scenes and can't get to the end goal...
You won't need much of a walkthrough, I think. There aren't any right/wrong choices while dating your chosen hasubando. As long as you raise their affection level, they'll take you on their following scripted event when you "Go Out" with them. Five "Go Out" events until you finally fuck on the fifth event. And when the game ends (the 22nd Session when you get to the map screen after Day 64), you go to the place to meet your chosen hasubando, get their good ending and unlock their After Stories in the Main Menu. You even have enough to time (and if you memorize their schedules) to date everyone to their fifth event, including the Lenga and the Twins.
I might feel like making a guide in the future, but as of right now I don't think the "True End" for the secret route is incomplete (or is bugged) so I'll abstain.
If you want to do things faster and reduce the amount of excess playtime, you can save edit your save file as the variables you want to edit are easily labeled. Just increase the affection level of a certain character to 500 or something and you won't ever have to gift them anything. Just "Go Out" and the event will pop up. You can also edit the amount of gifts you have and your mani (money) if you want to do things traditionally without the grind. Normally, you should increase their affection level by giving gifts (which means playing the god awful minigame) or maybe choosing them during the Spa/Sauna/Parade/Cosplay/Beach events.
I've also experienced not getting some characters' respective sex scenes in certain events (specifically, Sota). I think you need to increase their affection level or access their own events in order to fuck them during said group events. Another example is the threesome with Oki/Okan at the Beach event not being available if your affection level/heart level with both is too low.
You can also unlock certain NPC CG and threesome CGs that don't occur in game but become available in the gallery. Look for my post in previous pages.