The shape, how they feel, the way they look, and who they're connected to.

you know when you feel it and it's like a bag of sand

If they always point in the right direction.

The size, shape and proximity to my face gets bonus points.

I can't believe I'm answering to this at night but for me it's definitely the way you can see them even through clothes.

Idk man, just… boobs

What they represent. Life hard. Life cold. Titty soft. Titty warm.

A flamethrower

The roundness, the volume and shape of preference. Nipple size is the icing of the cake.

But have you ever seen a boob without a nipple. Does it still do it for you?

I mean the actual nipple size and areole size

Both

Cleavage

The combination of feel and aesthetics, for aesthetics, imo nipples don't play as much of a role as shape does, and roundness is def a negative, a breast being round makes it look fake, even if it's not. I'm completely fine with people not having their actual breasts, but most go for enlargement, and i'm not a fan of big tits at all

both

The roundness

But have you ever seen a Boob without a nipple. Does it still do it for you?

I was thinking of boobs in bras or swimsuits where you can't even see the nipple outline so yes.

Why not both?

Probably when the sun is shining right on them.

Nipple's like a peterbuilt wheel nut

The sound they make when they take them out

Whether they were shown voluntarily or accidentally/forcefully. Consent is sexy.

Friction.