You're not the only one .... I also love being tightly bound (preferably hogtied) and gagged in plastic or rubber. The longest I've been bound in my rainwear is something like 7-8 hours with my hands bound together in front of me and tied down to the bed so I couldn't move or escape. Another time, my now ex partner chained me to the bed in my rubber suit and plastic rainwear over this, with any number of chains, leather cuffs and straps before leaving me there while she went out for the afternoon. It was so boring being bound like this with nothing to do or see while I waited for her return, but it was also so exciting too. I was not, however, gagged for safety reasons though.
I'm hoping that Chel will be a lot stricter though and leave me hogtied all night in my rainwear ... now that would be an experience to savour!