Boyfriend called my sister hot..

Sydnee • I love dogs
We were standing there and I was telling him a story about how creepy guys always stare at my sister and I in public and he said "Well it's because you guys are hot as fuck." And I got mad at him and he said he didn't mean it in that way. But idk how else he could have meant it. Am I over reacting? Should I be mad at him?