It can imply "sex", insidious, dangerous and even overprotective.
Black and yellow are just warning colors.
So it's easy to understand
Snakes represent potential dangers, or ethics, laws, deviance, etc. What you want to violate.
Or represent a potential inner conflict.
Try to find out the contradiction
Sick turtle, a self-protecting creature, may map your morality, and its principles are threatened by the id (desire).