When you're doing seggsy time with a girl and are about to bust, so you call upon the tailed beast that your farther trapped inside of you when you were a baby, and bust the biggest chakra-infused load, practically flooding the room your in.
friend 1: "yo where were you the past few days?"
friend 2: "oh ye, well, I was stuck at home cleaning, me and Bella where going mad a few nights ago and I felt like getting Kurama in on some of the action and he ended up flooding the our bedroom with a Tailed Beast Bomb when he finished, haha"
friend 1: "WHAT IN THE MOTHERLY FU-"
As in 'Here is my new kindergarten class, all bright eyed and bushy tailed.' The allusion here is to the appearance of a squirrel, which with its beady eyes and bushy tail looks ready for anything. 1930s