Instructions unclear, as the question is almost phrased as how would my player react to a teammate sharing a night of passion with *their own* mother. In this case, and depending on the species and culture of said teammate, it would definitely taint Marek's view of them, as he comes from a fairly traditional family and incest is frowned upon. If its a step parent, then Marek has probably seen it already on the internet, and the locker room is full of high fives.

Now, if said teammate had a night of passion with Marek's own mother? The minimum punishment would be locker boxing. Marek does not lose in locker boxing. Marek would be intensely concerned about his parents relationship and the affect a disintegrating marriage could have on the brewing business they've worked so hard on. On a completely unrelated note, the beer brewed by Marek's father has recently become a favorite of some ahem, unsavory types around Pilsen and Prague. Guys with pseudonyms and multiple fake passports. It is unclear how his father might leverage those connections in these circumstances, if at all.