I had only heard of the Bermuda Triangle as the Devil's Triangle. I don't know if there was such a drinking game. Or the other meaning that's been suggested.
That yearbook sounds like the sort of talk that boys in all-boys' schools have, but I went to a mixed school so that wasn't my experience of being 17 or 18, and I don't know too well how to absorb it.
It's not the language of anyone having a relationship with a girl. That's for sure. It's strikingly immature. It says the sorts of things I might have expected of a frustrated 14-year-old with no experience, maybe. So a really pent up thing by aged 18.
I think that is the root of everything. Isolation between sexes is not without consequences.