Watch Chris Pratt And Jimmy Fallon Try To Say 'Titmouse' Without Laughing

"For being so small, they're very scary."

It's hard enough to master "word sneak" -- Jimmy Fallon's "Tonight Show" game of forcing guests to sneak random code words into the conversation -- when the topics don't include a songbird with a non-nonsensical, semi-dirty name, so we understand completely why Chris Pratt couldn't keep it together when "titmouse" showed up on the roster. (It isn't a tit or a mouse!)

Pratt, of course, was in town to promote his September 27 hosting gig on the "Saturday Night Live" premiere, and if his ability to commit to silly improvised material on "Fallon" is any indicator, it should be a really great show. Also, yes, Norm from "Cheers" really could have benefited from using a NordicTrack: