He cannot f**k himself, for he does not have the female genitalia to do do. Unless he is intersex or you mean anal sex. Even then, it is difficult to adjust your p**is to your anus, if possible.
There is a normal way to interpret this, and then theirs the even worse way to interpret this…
Either you showing that while females get periods, the males jerk off, or you could be inferring that their in the same bed…