I just got this badge (http://www.glitch.com/achievements/bathed_in_sloth_slobber/).
From my experience, it is very rare if ever to have two sloths spitting snails on you within less than 5 minutes. One glitch told me it happened to them, but I have my doubt.
So, here the easy way to get the badge:
- find a sloth you like and pass repeatedly in front of his tree. Usually 4 or 5 times is enough.
- go /home and do whatever you want, and or walk a resource route.
- do this for 5 minutes or more then /leave to repeat the sequence.
Good luck.