Hello Summer.
So if I understand you correctly, you are taking very similar asana classes (sequences, style, philosophy et al) in an externally warmed climate (hot room) and ONLY on Friday are you leaving with anger? And you also point out that the sequence on Friday differs ONLY in that you are doing a long hold in Pigeon (but no long holds in other poses)?
I’ll reply to this but I’d like to point out that liking a pose and having it feel great does not, in my way of teaching, equate with fidgeting and feeling like screaming. They are opposing principles, though having emotions come up is not.
Typically, hot yoga classes are also fast vinyasa classes. This is not always the case but it is more likely (and you haven’t said, so…). And such classes certainly have benefit but they also tend to attract or cater to a pitta constitution. Pitta is one of the three constitutions in Ayurveda, Yoga’s sister science.
If you are pitta in nature and doing a pitta practice you are adding more logs onto your fire and that fire can be consuming when not tempered or moderated. A pitta constitution is also often agitated by that which is “slowed” “held” “still” or “quiet” unless they are engaging a practice and diet that balances or they are completely and utterly exhausted such that their resistance is flaccid.
Because you are folding forward in the pose you mention, the nature of the pose itself is introspective. Typically there isn’t a gap in a fast-paced practice for introspection though it might be intended, thought of, or paid lip service. There’s not much introspection that can occur in a forward bend that lasts the duration of three breaths. So svadhyaya (the process of self-study) may not be a concept your nervous system and ego have been prepared for and they simply may be throwing an adolescent temper-tantrum.
The practice of Yoga doesn’t make us better people. It makes us more of the people we are. The practice of asana without an intention to evolve, bring light into the cells, explore alignment, infuse joy, and facilitate a connection to the heart instead of the vital and mental, this fosters ego, aggression, and anger.
Ask your teacher though. It is, to my way of feeling, important to cultivate the relationship with the person you’ve chosen to teach you the practice and that person should absolutely be able to say more to you than “uh huh, yoga brings up anger”. Get what you are paying for - the teachings of Yoga.