How can you tell if there’s sexual tension between two people?

How can you tell if there’s sexual tension between you and the person you like or just between two people?

I help out sometimes at the place the girl that I’ve liked forever works at. A lot of times she’ll pop out her chest 4-5 times in front of me, flip, curl, poof up her hair constantly, laughs 95% of the time, rubs thighs, and all other kinds of stuff.

One time she was sitting across from me and she kept taking her phone out and away and out again. Her phone was in her waist band. And I swear to God each time she took her phone out, she moved her shift higher and higher every time to where it was a few inches over her belly button. Seemed unnecessary. Then another time she was sitting across from her manager when I had to leave. She turned her whole body facing me and she had her legs wiiiiiiiide open. And I’m pretty sure girls don’t just randomly subconsciously do that sort of thing in front of guys. So I’m pretty sure that was a message,

Other times if we’re standing near, she stands extremely close or if showing me something she gets close to my face when she could just point. But for the last few months we keep getting interrupted or the owner gets on our way of talking to one another. And I feel like there’s a feeling between both of us of getting annoyed at getting interrupted. Each time I’m about to ask her out or ask her to try and throw me off the mechanical shark we get interrupted.

So like I said we have a very natural chemistry, I feel like she’s showing plenty of hints. But how do you tell if there’s sexual tension? Because sometimes I wonder if there is that on both sides with us. Sorry for length.
How can you tell if there’s sexual tension between two people?
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