When we're talking about the examples people bring up in this comment section to illustrate high chargeback rates ("Uncle Derek bought a $500 subscription in a stupor and his wife is about to find out"), the definition would be something like "live action video recordings of humans engaged in sexual activities". Explicit content is a superset of that, also including all the other examples I gave.

Note that I'm not saying we should ban that. I'm just saying that if the 'unbearably high chargeback' excuse had merit, they would've been precision-striking just those categories of sales, instead of opting to nuke everything that humans find sexual, regardless of medium, type of product/service, artistic merit, popularity and so on.