No.

Your body unconsciously begins to hump the air and that slight movement is enough for your cock to erupt. You let out a long moan against your wife's ass as your cum sprays out onto the ground. Most of it goes under the bed which is good as your cock pulses seven or eight times. Hopefully your wife won't notice; you've no longer got any idea how she would react if she found out that worshipping her ass not only made you harder than you have ever been but made you cum without touching yourself. Your wife collapses forward onto the bed and you move with her, continuing to lick and suck her ass. Your wife pushes your head away with her hand.

"Oh my god enough, honey."

You regretfully stop, and wipe the saliva off your mouth with the back of your hand. Your wife rolls over and sits up. She checks to see if you are hard with her foot.

"Really? All that and you still couldn't get it up." You play along, knowing you can clean up while your wife is asleep. "Ok, get on the bed. I think I know what you need." You do as you're told and lie down on the bed.

"No, not like that. Like this..."