not just by merit of having sex, at least? if you agree that's the case, then yes; otherwise no

No.

Nope

You're never in an actual relationship until both people explicitly acknowledge it, there can't be any confusion

No,not automatically.

Did that once, like putting on an old pair of shoes, Then u remember why u threw them out lol No it doesn't mean ur back together unless u both want to be.

lolno, sounds like a rebound if there's nothing more

Nah. Needs always to be spoken about what one is or isn't and no assumptions made.

Don't wanna set a flame in her heart

Only if you stay there past sunup. I don't make the rules

No. That’s a dangerous assumption to make. Both parties should clarify their feels/expectations.