Interesting! Member Berlin1994 sais that POIS "Improves after taking a strong coffee and hot/cold(alternating) shower. Feels like pain is being flushed away." and I think that other members also are getting effects by cold showers on their neck area
after orgasm. Well, when the blood vessels are exposed to cold they are constricting and when they are constricting they are probably not leaking so many substances into the tissues, including pro-inflammatory prostaglandins. So if that happens in the right window where the inflammation is started, the POIS might not get a grip of you.
There are also studies showing that more cortisol are beeing releases in cold temperture; In this study authors conclude that " cortisol levels in cases of hypothermia were three times higher than those in other causes of death" (
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7028257/). Also, coffee, or rather coffein, increasing cortisol, vasoconstriction and reduce blood flow. So thats why some members reduce symptoms by having a cup of coffee after orgasm. However, coffee is also decreasing testosterone in the long run (only one cup of coffee significantly lowers the testosterone during 24 hours). Maybe because it stimulates cortisol and cortisol steals building blocks for testosterone (cortisol is always the priority 1 hormone). Conclusion: Cold temeparture, cold showers and coffee might work wonders when taken in
the correct window after orgasm, but other than that, I believe it is very contraproductive to POIS.