When do you think men lose their virginity?

[Insertnamehere]

There's no male equivalent to female "virginity". The whole concept is more of a social construct based on an observed anatomical change build solely to keep women in check so they could be traded like assets with greater added value.

Keeping this in mind, we could equate male loss of virginity to the first time he penetrated/got penetrated. Fairly simple.

As for bodily functions, we could pick either I guess, but then we would have to re-define women virginity in those same terms.

That said, the best thing to do is to simply speak on terms of when does each gender reach sexual maturity. For women, a few days before her first period, for men the around when they notice their first nocturnal emissions.