In MGI sex is the goal, not main mechanics, and relationships somewhat matter. So feffing about is expected. It's hard to make sex interesting mechanically for long playthroughs.
About minigame and gameplay in general:
Game is incredibly stupid and should be approached as that. Every character there is total idiot, including your character (not sure about monocular cockblocker, she feels like a mastermind in comparison to everyone else). Every element of the game is idiotic, almost insultingly so, only wolf and spear fishing are "gamey good".
I can enjoy MGI only after turning my brain off completely, tried to play it as normal game first time, almost died of cringe and most likely got permanent brain damage (that explains why I spend so much time here now).
It's cringy in many ways due to messy and childish character writing, but "brain off" mode helps with that.
But cringe is especially painful in sex related interactions, in that either you manipulate, abuse and rape girls, or they are raping and abusing you. Only NSA Put Backdoor In My Fox and Purple JiggleBitch are somewhat fine, both are horny and openly so.
Monster Girl Island: Battle Royale - "Rape or be Raped"
So disable your human brain, activate your lizard brain and game will be much more fun.