A reference to the massive amount of donations sent by YouTube stream watcher Matt Gagnon, who is notorious for donating hundreds of dollars to streamers out of the blue.
A galoon is a gallon of the cheapest wine which means it is usually made from the residue of other wine pressings.
On the weekends we boys in the navy got drunk on a galoon of pink wine each cause it was cheap and fun to say - let's get ourselves a galoooooon of wine!