When the penis is soft, the dick collar is the loose skin that bunches up around the base of the head, or neck, of the penis.
Thus creating a collar-like appearance around the base of the head.

Solarpunk is a movement focused on a positive, ecological vision for a future where technology is used for human-centric and ecocentric purposes. It is a literary, artistic and aesthetic sub-genre and is also closely tied to eco-political activism. Solarpunk narratives have a distinctly positive and utopian foundation in contrast to the often dystopian visions found within other "punk" science fiction genres.