Suggestion from yet another person who's had a job wearing a giant character costume in the middle of summer in Cali...
You know those camel water pack things? The ones bikers use to keep hydrated while on runs? I'd get one of those. I'm not sure on the cost and whatnot... but I don't think they're too expensive... and as good as it is to stay cool, it's better to stay hydrated (It took years of marching band to finally drill this into my head, XD!). And with that you wouldn't have to be constantly taking the head off to get a drink ^_~. Just keep the straw/tube part in your mouth ^_^.
But yeah, I was supposed to have one of those water things for the job I did... but it got lost (I wasn't the first to have to wear this 40+ lbs costume... fyi: it was this giant blue panda bear named Big Billy and I wore it for a Women of Faith convention in San Jose... in early August x_x... I need to scan the pics of it... was really fun... the shoes were twice the size of my head, XD!)...
Anywho, awesome job ^_^. Yoshi is one of my fave characters ^-^.
I've been wanting to do something like this myself, but can't decide on a character ^^;... Oh well... I have too many other cosplays I'm doing... maybe next year ^-^.
Good luck! And you've got yet another person here who will glomp you if she sees you, lol!
RIP Josh Smith
(1987 - March 23, 2004)
He's skating in heaven, Bre... and drawing smilies on everyone he meets.