Never had a crush, but
A for me a squish is:
The interest is mostly intellectual curiosity. I want to talk to them, hear their ideas, I enjoy the way their brain works.
I enjoy their company. I feel comfortable and relaxed if they are around.
I think about them a lot, reminded of them by stuff. Like I'm at work and someone shows me a picture of a lapel pin that is also a flower pot, and I instantly go, "not really my thing, but XY gonna love this so much, I'll send them a link". I want to show them my favourite places. I want to show them my favourite music. I want to show them the books I like. Things like that.
I don't want to flirt with them or flood them with random compliments. Alloromantic people tend to switch into courtship mode when they have a crush. I do compliment my friends, especially if they have self confidence issues, but the "I like your hair...I like your jokes...I like your eyes...I like the way you hold that pencil...I like the colour of your belly button" thing just seems excessive? I never had the urge to say things like that in such frequency.
I'm fully functional when they aren't near me. Alloromantic people tend to act like abandoned puppies when their crush is out of sight. I do miss my friends if I don't see them for a while, and I am really excited and happy to see them again, but never really had that intense longing.
No jealousy if I see them with someone else they "like" like(d). They can bring along all their exes to whatever we are doing together, I don't mind. I'm actually happy to meet the people who already passed the "decent human being, good friend material" test by someone I consider a friend.
I don't want exclusivity. Pretty much what it says on the tin.