I have no idea why that happened; I have done quite a bit of meditation over the years but never had an experience like that. However that is absolutely hilarious ahahahahaha "smells like poo" hahahhahahahahahahah I Love it hahahahahahah well that’s certainly something I would never expect to wake me out of meditation hahaha. Wonderful!!!
You should be happy that your mind is creating really funny images. I bet you are a really interesting person.
A technique my mum taught me as a child is to lay down in bed and focus first on your feet, say "good night feet" and let them fall heavy asleep, then focus on your ankles "good night ankles" etc until the top of your head. That usually sends me right to sleep! hhaaah