Bringing loads of milk up while still feeding

[OrangeFootedScrubfowl]

In a huge projectile spray.
Everything covered in vomited up milk. Me, baby, sofa, carpet...

Why would that happen sometimes? Is it something I am eating occasionally?

Assuming baby is otherwise well, lots of wet nappies, yellow poo, gaining weight... Probably just wind propelling the milk back up.
My ds used to do that occasionally when I fed him in a certain position. All over he sofa. Very rude.

But if it's really projectile, not just "blurted" up and it continues you should see a doctor ASAP. True projectile vomiting is indicative of a specific gut problem that needs treating. How old is baby?