what is the meaning of "I'm behind" in this situation?

[mokbon]

Hi

in this situation, Does "behind" means Chandler supports this experiment?
"behind" is back from the one, so could it also means that he won't participate?

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Ross: Look, if she's talking to it, I just think that I should get some belly time too. Not that I believe any of this.

Phoebe: Oh, I believe it. I think the baby can totally hear everything. I can show you. Look, this will seem a little weird, but you put your head inside this turkey, and then we'll all talk, and you'll hear everything we say.

Chandler: I'd just like to say that I'm totally behind this experiment. In fact, I'd very much like to butter your head.
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source: Friends s1 ep9

[mykwyner]

Hi

in this situation, Does "behind" means Chandler supports this experiment?
"behind" is back from the one, so could it also means that he won't participate?

-------------------------------------------------------------------
Ross: Look, if she's talking to it, I just think that I should get some belly time too. Not that I believe any of this.

Phoebe: Oh, I believe it. I think the baby can totally hear everything. I can show you. Look, this will seem a little weird, but you put your head inside this turkey, and then we'll all talk, and you'll hear everything we say.

Chandler: I'd just like to say that I'm totally behind this experiment. In fact, I'd very much like to butter your head.
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source: Friends s1 ep9

Yes, that's exactly what it means.
You would never be behind something you weren't in favor of.