...are obsessed with their mom's boobs?

My LO has been incredibly clingy lately. I'm talking "not even wanting to go into the wading pool because she would rather leech onto my back" kind of clingy.
When she is in this kind of mood, her hand is constantly in my shirt. In my shirt while she's watching Sesame Street, in my shirt when a stranger comes up to say hi....it's like they comfort her just by touching them?

Are all kids like this? Just breastfed ones? Maybe it's just a general toddler thing?