This looks like the sort of cartoonthat would feature a dildo tree or a fisting bush (fnar!), so I expect it is the sound of some form of anal or vaginal penetration from the foliage, yes.
(
wheelybird mreee!,
Mon 1 Sep 2008, 16:06,
archived)
it has to be analI doubt you'd get a duf from her soppy distended animal twat.
(
Wasp Box like a nervous random stranger at a glory hole,
Mon 1 Sep 2008, 16:21,
archived)