I actually find it cute that Skamm reacted with extreme jealousy despite not being paired with Kir officially; I'd find the jealousy he displayed inappropriate because the two are not an official pair (and thus, Kir has every right to get hot and heavy with anyone else). However...
I do question that mentality. Granted, being yiffy often and regularly is expected in Yiffburg, but as seen in Fleecer's introduction to Yiffburg, people don't yiff 100% of the time: they skate, they have picnics, they socialize without being sexual. What if one partner of a monogamous pair decides he or she wants to have fun in a nonsexual way and the other is feeling yiffy? To my knowledge, having sex with a partner not in the mood tends to ruin the experience for both, and I am pretty sure Yiffburgians frown upon adultery. Yes, swinging and having multiple partners is definitely allowed, but not everyone is a swinger, and the thing about swinging is that both partners consent to having sexual relations to someone not being married with/paired to them. So in a scenario wherein a pair isn't mutually yiffy but are otherwise monogamous, how can jealousy displayed from the one not being in the mood be frowned upon justifiably? I can't imagine how because he/she is exercising his/her right as one half of the monogamous pair to not consent of his/her partner getting it one with someone else not him/her. It's like an entire society frowning upon you because you want your partner to remain faithful to you when you two agreed to love and shag exclusively with each other."This is a social club, and in yiffbug, being social means being yiffy! Jealousy is frowned upon... If you're not in the mood, you musn't get upset at someone who is!"
I hope Kir's reprimanding of Skamm's jealousy is only a result of displaying said jealousy when the two are not officially together. Otherwise, if the two are monogamously and officially together, the implications of Yiffburgian society frowning upon being jealous towards his/her partner having adulterous sex without the other his/her knowledge or consent is rather unfortunate.