Fillion does a pretty good job, and he makes his character a wee bit more interesting than it might have been (just like Adam Baldwin always does too). He's extremely passive, and you can see him looking at the director to be told where to stand and what to do. Which I think is cute.
There's a discussion on metafilter about whether it's misogynist, or making a point about misogyny. But I don't think it's as deep as that, I think it's just a bit of a daft joke.
ETA - but it does have a violent (accidental) death, so be warned. It may be that's the point, that violent death is PG and a blow job is not.