1. He's touching your back and trying to bring you in closer, not thumping you on the back after a funny joke. Not all physical touches are flirtatious. A good guide: If it feels like you're in the scene in Step Up where Channing Tatum learns to dance, he's into you.

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2. He's not so slyly trying to get your number. Hey, he has this great video of a cat you need to check out later! And also he has that group shot of you and your friends and just needs text it to you. Why doesn't he just text it to you now?

3. He gets way too animated when he finds out you're both into the same stuff. He treats the revelation that you've seen Imagine Dragons live more times than he has like he just got news that scientists found a cure for cancer. Because loving Imagine Dragons together is an integral part of his dream relationship.

4. He's whispering. Guys who like you never speak at full volume. It's science. Maybe the two of you are leaning against a kitchen counter at some house party giving each other the gossip on everyone there, or propped up at the bar going on and on about something no one else cares about. If he's trying to break the ice by making you feel like it's just the two of you in a sea of other people, that guy is trying to mack it.

5. He won't leave your side. Not in a creepy way; he just has no interest in talking to anyone else at the party. If he's been given exits to leave the conversation and he hasn't taken them, he's either into you or you're explaining how you have successfully practiced alchemy.

6. He's joking a lot about sex. This is a weird one. Too much sexual innuendo is so, so creepy, but if he's being playful and making you laugh with his double-entendres, he's trying to see if you're OK with the thought of him and sex, maybe together, maybe tonight? Dick jokes are like sounding rods for conversationalists.

7. He's grinning, not doing that polite, rehearsed photo-posing smile everyone has. Sometimes people just smile because they're friendly. But if he's really grinning at your stories and jokes, that's an "I'm into this girl and everything she's saying" kind of a smile. If he's smiling and politely nodding, that just means he doesn't want to tell you how boring your story is.

8. He winks at you. Winking is always flirting, always. The only time winking isn't flirting is when someone is just really bad at blinking.

9. He's really going out of his way to do something nice for you. Buying you a drink at the bar is one thing, but if he's offering you a ride home or suggesting you study together for a final, or he comes by to help fix the leaky showerhead you mentioned, he's trying to make sure the two of you can see each other again.

Related
18 Ways He Secretly Says "I Love You"11 Explanations for Why He Hasn't Texted You Back

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Cosmo Frank
I am a human male that enjoys consuming meals consisting of all five food groups and fulfilling every level of Maslow’s Hierarchy of Needs. I write about sex-having.