Weird ass dirty talk?

My boyfriend recently told me after sex that he really likes it when I compliment his balls. I don't even know how to do that! With his dick it's easy. "You're huge and thick" yknow whatever. Guys like to be told they dick is big. But balls? What do I say? They feel like if somebody took saggy chicken skin and filled it with an uncooked egg yolk. Like what does he want to hear? They're big? They're soft? Are those even compliments ? Helppppp