rule 34 2011 3d abs anthro balls bovine cattle cloven hooves contrapposto digitigrade erection glans grey background hand on butt hand on hip hand on penis hooved fingers hooves horn humanoid hands humanoid penis looking at viewer male mammal model model sheet muscular muscular male navel nipples nude penis pose realistic retracted foreskin sculpt simple background solo standing tail tuft tergos thick neck three quarter view tuft uncut vein veiny muscles zbrush 2657114