What does this sentence mean?

I guess it means "we're acting as if we were under the influence of drugs", but more context would help.

Thank you,
I think you are right. Their basketball team played very well and his friend (a girl) doubted how they could play that good.

The girl says:
I've just never seen a team play like this before, it's...
And then the boy says:
So we gotta be on something?

And the girl:
No. I didn't mean for it to pop out like that.

Yeah, pretty much what I said earlier.

I've just never seen a team play like this before.
(You must have taken something—probably some performance-enhancing drugs.) -- that's what the guy thought she was implying.