If you're interested in experimenting with ways to help yourself last longer, here is a pretty unique one. I'm not an orthodontist, so take this with a grain of salt. This is just what my understanding is.
You may not think it, but your tongue can carry tension (LeFevre, 2017). Just ask any singing teacher. This tension in your tongue, which affects its position in your mouth, can have an impact on your temporomandibular joints, where your jaw bone connects to your skull (Rosa et al., 2020).
Impact on the temporomandibular joints can affect the trigeminal nerve, the largest of the nerves in your face (Pedullá et al., 2009). Stimulation of the trigeminal nerve can trigger the trigeminocardiac reflex, which influences heart rate (Meuwly et al., 2017).
It has been found that clenching of the jaw is associated with increased heart rate (Yap & Chua, 2016). In fact, people who suffer from bruxism, which is excessive clenching of the jaw, have been found to have higher levels of the stress hormone cortisol in their bodies (Flueraşu et al., 2021).
It is known that elevated heart rate is associated with sympathetic nervous system activation (Gordan, Gwathmey, & Xie, 2015). We also know that the sympathetic nervous system plays an important role in the expulsion part of ejaculation (Clement & Guiliano, 2016), as well as contributing to the etiology of premature ejaculation (Xia et al., 2014). I've spoken at length about this before.
In layman's terms, all this is to say that if your tongue is tight it'll make your jaw tense, which will increase your heart rate, kind of like how we clench our jaw when we're angry and our heart rate goes up. This will activate your sympathetic nervous system, which will make you cum quicker.
So, relax your tongue. Apparently, when you position your tongue on the palate rather than on the floor of the mouth, there is a significant reduction in heart rate variability (Schimdt et al., 2009). Try some tongue positions next time you're trying not to bust and let me know how it goes.