Yes, that’s the body position where the spider silk is made. But spiderman is wearing trousers (and underpants I suppose).

There was a (ig nobel prize winning?) study which asked the question if someone could pollute a clean or sterile environment by farting into it: The team of scientists concluded that it is safe (regarding… particles) as long as you wear underpants/ trousers. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121900/)

So…