rule 34 2021 anal anal egg implantation anal sex animal genitalia animal penis anthro aphrodisiac aphrodisiac mask balls canid canine canine penis canis digital media artwork egg egg implantation erection fucking machine fur genitals gradient background green eyes hair hi res knot laboratory lying machine male male only male penetrated mammal mask on back orgasm factory penetration penis raine riverwind rainingrush restraints science science fiction sex machine simple background solo solo male tentacle text twink wolf 4603833