Pisces Capricorn compatibility question

So I am a Pisces girl, and I am falling fast for this Capricorn guy. Everything I read says that Pisces and Capricorn are very compatible. But he was born on the sagittarius-capricorn cusp, and sagittarius is one of the least compatible with pisces. And i was born right around the pisces-aries cusp, and aries is one of the least compatible with Capricorn. However, everything I read says that Aries and Sagittarius are very compatible also. I'm just not sure what to think. This guy is VERY attractive and we flirt constantly.

He's always trying to get me to make out with him and get me to give him a BJ, and tries to take my clothes off all the time. All of our friends say they're just waiting for us to finally realize that we like each other and start dating. But at the same time this Capricorn guy is such a jerk to me sometimes. He's constantly making fun of me, and ignores me when i try to talk to him, but still continually flirts with me. When he's being flirty hes very sweet and romantic, and i can tell that he likes me.

But when he's making fun of me I don't understand it. He goes from completely ignoring me to trying to being REALLY romantic with me. I am so confused now and I don't know what to think. Sorry this was so long, but I would really appreciate any comments or advice you have.