Well an env. filter would be good for consistent wah-ing... but an actual pedal obviously has more control. You can slowly build the wah through a whole 4 measures, then wah wah wah the next two.
...I gotta gets me a wah pedal.
And the third little piggy went wah wah wah all the way home. ....which reminds me of:
YouTube - Green Jello "Little Pig, Little Pig"
uh, word of caution. I think it's clean all the way through. *might be some lang. though..... I apologize if there is.