Aw, man! I'd forgotten this existed. My gf and I used to do the "mah mah mah mah", "oh toh toh toh"-thing when pouring drinks for each other. Thanks for posting it and reminding me.
What does that actually mean? Is it a reference for something people do in Japan?
The person who the drink is being poured for is saying that it's too much and it's about to spill. The person pouring the drink wants to continue pouring out of generosity. "o-to-to" (sort of like "oops") and "maa maa" ("no no" / "doesn't matter") are normal things for the respective parties to say in this situation. It just won't go on for that long, or be done every time with those exact words like a ritual, which is the joke.
if party of one you should feel a little shame! wow.