Of course, I could be wrong, but a date with Beth seems to be necessary, without it it is impossible to advance through the main plot and Mia’s route.
And it would be okay if everything was limited to the scene of “milking” the stallion with her hand, but then you can find out that Beth allows herself in her relationship with the horse that my wife still does not allow in relation to me (JOKE)
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I will be very glad if Tinkerer reworks these "controversial" things, because this is one of the few things that I personally did not like in this wonderful game. There is also, of course, a completely unrealistic grinding system, but you can bypass it by installing a cheat mod.