"I don't want a serious relationship I just want someone to mess around with"

You, and everyone ever. Throw this out of your brain. It serves you absolutely no purpose. I see people every day be hesitant or get caught up in this label bs.

You still do the same exact thing regardless of what you want to call it. Your job is to charm and have sex with the girl. Let the girls do the labeling and be responsible for locking you down.

Scenario 1: "Serious relationship" - You game the girl, you have sex with the girl, the girl asks you if you want to be gf/bf. You say yes and establish that the two of you are exclusive and are headed for the long term

Scenario 2: "Messing around" - You game the girl, you have sex with the girl, the girl asks you if you want to be bf/gf. You say no, you want to have fun. Okay.

So there's no difference in the process. You do the same shit. So everyone from here on out, stop getting hung up by what you do and don't want from the girl on a long term scale. Focus on getting the girl to a point where you're in the position to choose.

And yes dude. If you feel like the girl likes you, the girl likes you. Game isn't logical, its visceral. We've been on this planet for millions of years fucking one another and we've become experts at knowing when people find us attractive. Study some biology, there's literally hundreds of micro level detections and behaviors that happen.

What other option do you have than to invite her out? You going to just sit around and beat off and then in 6 months go "I wish I would have talked to that girl"? I've done the latter and it doesn't accomplish shit, so I'd recommend inviting her out.