While squatting over a ho, or being on top of a ho during 69, and she is in the act of sucking on your nuts, you position your asshole directly between her eyes and fart.
An eye drop is when your pop out the glass eye of the woman you’re making love with and stick it up her anus. You then put your penis in her eye socket and she whistles “Steam Boat Willie”. Afterwards, she poops her eye into your mouth, you swoosh it around and clean it, then spit it into her eye socket.
A crush you don't wish to pursue. Either because you know it wouldn't be a good match or because they already have someone else. So you are happy just looking at them occasionally like eye drops that fill your eyes, but do nothing other than that.
A: Hey, you've been giving them looks for a while, will you ask them out
B: No, they're just an eye drop crush.