Rule34.GG

Regular alien abduction
anthro
anus
ass
ass focus
backsack
balls
ballsack
bottomless
bottomless male
bound
butt focus
captain stryker
captive
clothed
clothing
conditional dnp
exam table
examination
experiment (disambiguation)
foreskin
genitals
imminent anal
imminent rape
laboratory equipment
legs held open
legs spread
looking back
looking back at viewer
male
male only
mammal
mechanical fixation
metal
mink
moodyferret
mustelid
musteline
partially clothed
penis
perineum
presenting
raised tail
rear view
science fiction
scientific instrument
shackled
shackles
solo
spread legs
tail grab
uncircumcised
uncut
uniform
worried