Meaning
A man with a rounded, pregnant-looking belly. It was added so that trans men and other people who carry a pregnancy can be represented, alongside the pregnant woman and pregnant person. It supports skin tones.
Besides its inclusive purpose, it is widely used as a joke about a full stomach after a big meal or a growing beer belly. Both readings are common, so context matters: βTwo plates of noodles and dessert, I think I am expecting now π«β