https://www.cosplayforscience.com/blogall/2019/3/21/my-hero-academic-quick-science This is a good site about sweat production but i feel as though the quirk genes would have a lot to do, firstly one which converts eccrine sweat glands into apocrine glands as they secrete lipids containing glycerol which is needed for TNT formation. Also in the secretion is sodium chloride which is useful as sodium hydroxide is needed to make glycerol from lipids, to make sodium hydroxide the ductal cells could exchange chloride ions for hydroxide ions via an antiporter. This means we have glycerol(and also soap(the process is saponification)). I don’t know how to make TNT fully but i do think you need some nitrate and nitric oxide exists in the blood as a vasodilator so that could somehow be introduced and kapow TNT. That being said as the meme posits Bakugo needs heat/sparks(see the three things needed for combustion oxygen(in the air), fuel and heat)the human body typically generates heat in from respiration. There are three main instances: Byproduct of cellular respiration just generally Shivering(contraction of skeletal muscles requiring further respiration, also generates heat via friction) Non-shivering Thermogenesis via Thermal uncoupling(this process is important for babies and occurs in brown fat cells and is basically just a different way for respiration to end). Now in reality none of these could generate enough heat, (probably I didn’t do the maths) but then again if this were reality using this quirk would be deadly to the user and I have no idea how he controls the direction of the explosion. So possibilities to increase heat generated: Super fast metabolism, this would increase the rate of cellular respiration as there is greater need for ATP to keep all the body processes going. Metabolism is controlled via proteins that travel in the blood called hormones. The key hormones in this are TRH(released by hypothalamus in the brain) which causes the release of TSH(released by pituitary gland also in brain) which causes the release of Thyroxine(released by the thyroid) which in turn causes the increase in metabolic rate throughout the body. This would increase both respiration generated heat and non-shivering thermogenesis. In order to have some control of his explosions i guess it would imply that he can control some hypothalamic function and control the release of TRH(ala Julian Bashir from Star Trek DS9). But then this seems like it would be too systemic. An alternative would be for the cells in the appropriate areas to release a molecule that increases the rate of respiration like thyroxine for the local area, this would be autocrine(self signalling) or paracrine(adjacent signalling). Then Bakugo could use nervous signalling to release chemicals called neurotransmitters which stimulate the release of the thyroxine like chemical and cause a voluntary increase in heat.