[Vocabulary] What is the meaning of "two dots" in this sentence?

[Farshad.021]

Hey guys, hope you all are doing great.

My question is about the meaning of "two dots" which I heard in a TV series called "The odd couples". It's a comedy.
First I'm going to give you the context:

2 men and 2 women are together for dinner. A man called Oscar asked one of the girls: Where is your sister?
She said: she's in the bathroom throwing out. Oh I'm just kidding, she is in the bathroom, and she eats a lot and still looks like that so only two dots to connect here.

I don't understand the meaning of underlined part. Does it mean that "she eats a lot and still in shape so we can figure out the reason why she is in shape as she always throw out or something"?

I am a bit confused because when she said that the people behind the scene started laughing.

Thanks in advance,

 

[teechar]

I think you'd need to provide more of the context.
In general, "connect the dots" means to relate various pieces of information together.

 

[SoothingDave]

I watched this last night. "The Odd Couple" (singular, not "couples")

Have you ever seen "connect the dot" drawings?

The joke here is that, in this case there are only two dots which need to be connected. One being that she eats a lot and the other being that she is still attractive/skinny.

The implication being that she is bulimic.

It's "throwing up," not "out." Regurgitating. Vomiting.