She's
1. An adult.
2. Single.
There is absolutely nothing wrong with her choosing to have sex with anyone at all. As long as it's legal of course.
What
Mangamoz is saying is that Toki-sensei looks like the kind of girl that would fall prey to a playboy that will fuck her a couple times them threw her out, the kind that does fuck and run and leaves women knocked up with twins and no dad to look for them
All that is legal but is nasty work, also those are the very kind of men that will insist on trying to go bareback and have no pull out game, unless it is pulling out of the relationship, sleazebags and scoundrels
And Toki-sensei deserves better than that, BTW the ugly bastard archetype also belongs in that group, that's what the bastard in ugly bastard is all about