It's Sleep Time (Patreon)

Mom Nature protects the forests from bad people who want to destroy them, and during one of her rounds she came across kidnappers who took a human to be a kind of offering to her, and when she saw that she got furious and got rid of the kidnappers , the way a hungry snake would.

After that, she took in the injured human and cared for him until both developed affection for each other, to the point that the human felt comfortable spending a few nights inside her tail.