God, it's hard to resist to NOT tell his feelings. You were best friends since he came alive, but he had a crush on you because of how Finn felt about you before he came along and wanted to feel that as well. To feel human.

He hated that his dumb little grass heart beated fast around you or made contact by holding hands or hugs. He wants to rip his heart out and squeeze it to avoid awkwardness, currently you were having a sleepover with him and you forgot your handmade sleeping bag so he unconsciously told you that you can share with him.