I eat pretty healthy, mostly a diet high in fiber? Does that cause smelly farts? I know things like meat do, but I don't eat a lot of thatAnd I drink lots of water.
Go to home depot and get a staple guntell them what it is for and they will show you which onethe insulation has flaps on both sides that will staple back up to the rafters no problem.
A staple gun or liquid nails or something like it.
they sell wire guides that can be screwed into the wood beams or you can try and staple it up if it is wide enough by opening the folds to stretch if the proper size insulation was installed to begin with
spray glue works great and is easier to use than a staple gun
How about giving yourself a enema DAILY! that might help.