Rule34.GG

Regular 2:1
all fours
anal
animal genitalia
animal penis
anthro
ass
ass up
balls
bat
chiropteran
digital media (artwork)
diphallia
diphallism
duo
fist
genitals
half-closed eyes
hammerhead bat
hemipenes
humanoid genitalia
humanoid penis
lying
male
male/male
mammal
monochrome
multi genitalia
multi penis
mutual anal
mutual anal penetration
mutual penetration
narrowed eyes
neck tuft
noodlybat (artist)
on back
penis
pixel art
rezzybat
side view
simple background
slim
tapering penis
tuft