Something is terribly wrong with this scenario. The Bottom (the man getting his ass fucked) isn't really showing any pleasure in having his ass fucked by his Top (the dude penetrating his ass with his erect penis). From the looks of the graphic, the bottom has his back correctly arced but he still isn't displaying any sign of gratification.
Maybe he's just not "into" his partner? Maybe his man's penis is too small to afford him any joy? Perhaps the man fucking (penetrating) him isn't going deep enough or hard enough?
Either way, this situation is more common than many think. Both men should be enjoying the sexual experience. That's one of the major reasons that we have sex. For the pleasure and satisfaction that it brings to us both. If we're not feeling the benefits, why go to the trouble of the sexual act to begin with?
A good partner goes to the trouble to discover what his partner likes, wants and needs. This is a two-way street. Otherwise, we could all masturbate without even having to leave our own homes. The responsibility of sexual pleasure is on both partners. None of us are mind-readers. Communicate!
Do you know what your partner enjoys?
Take care and stay proud and bare!
ReNude Pride