Stupid problem with easy solution. Just go to a brothel. Idk what's the sitch, but the fate of the kingdom or some grand thing like that is probably more important than who to lose your virginity to.
The demon king adding the virgin rule is the funniest thing they could've done, and it worked perfectly.
Would have a slightly more logical explanation like a prophecy saying "you will be slain by the purest of heroes".
everyone sure seems good at faking these numbers but like real talk hello Demon king what kind of rule is that ??? Non virgin.....??? Demon king gonna a end up a busty (or loli) waifu at tvis rate