you may insert a penis
, or dick
Also, by calling someone a dickhole, you are inferring that they themselves are not only chock full of orifices
that are readily insertable
into, they also are frequently used.
Almost like a magnet or black hole, they seem to draw dicks towards and inside them.
"Aw, yeah, this dickhole is so tight! It feels good on my dick!"
is a giant dickhole, cramming as much cock as she can into her dickholes."