MommyJacking 

When a person's conversation/comments/Facebook status is followed up with something about their friend's children, when it has nothing to do with the conversation. The "Mommy" just wants to steal the conversation to speak about their children. As defined on stfuparents.tumblr.com.

A classic MommyJacking
"Did I tell you where I went to dinner?"
"Oh that reminds me, little Johnny did the cutest thing at Red Robin last night!! He ran screaming around with a balloon for an hour!"

MommyJacking by Sloan3 January 13, 2010

Mommyjacking 

A mother commenting or replying to a post where she diminishes someone else's achievements and elevates her motherhood as more important or difficult.

Person: "JK Rowling is amazing!"
Mommy: "Being a single mom is probably a lot harder than writing a book, and I think JK Rowling would agree."
Person2: "No mommyjacking."

Mommyjacking by Sleeb February 17, 2017

mommy jacking

When a mother interferes with any conversation or activity to boast about herself as a mother, or of her children

Don't invite Karen, she is mommy jacking every conversation at girls' night. Nobody cares if little unvaccinated Julie can count to ten in Mandarin backwards while juggling non-GMO, free-range, organic fruits

mommy jacking by Willem Dafoes Junk May 25, 2018