We had planned to go running but it was pouring outside: cats and dogs and lions and tigers and bears. “We could walk the stairs,” I suggested. Our beach house had 15 steps up to the second floor. “Fifty flights would probably only take about half an hour,” I told Emma.

Emma frowned. “That sounds kind of dull,” she said.

“Yeah, but we could do it naked,” I added.

Emma’s eyes brightened a little bit.

“And as added incentive,” I said, “we could kiss after a certain number of ups and downs.”

“How many ups and downs?” Emma asked.

“Two,” I proposed.

Up and down we went.

Up and down, up and down. I have to admit the kissing was a lot more fun than the stepping.

We’d done about a dozen flights when Emma broke off the kiss to say, “How about as an additional added incentive when we’re done we fuck?”

That sounded great to me.

Up and down, up and down. At last we were done, breathing heavily on the bottom landing. For a second I thought we might be too exhausted to claim our additional added incentive, but that turned out not to be a problem: me seated on the second stair, Emma seated on me.

Up and down, she went, up and down, up and down, up and down. Fifteen minutes into the fuck she came, her arms and thighs and everything about her clasping me, her cunt clenching rhythmically. When she’d caught her breath, I suggested we go up to the bedroom. In reply Emma restarted the fuck. Up and down, up and down. It took her about ten minutes for the second come. Some ten minutes after that I joined her for the third.

“That was fun,” Emma exclaimed, her cunt giving my cock a goodbye squeeze. “How many calories do you think we burned?”

I retrieved my cell phone from the living room and looked it up. “Since you’re a lot lighter, your calorie total was somewhat less. It looks like going up 750 steps burns about 127 calories. More for me, since I weigh more.”

“That’s not fair,” Emma said. “What about going down? Does that subtract calories?”

“No, going down gets you an additional 37 and a half calories.”

“More for me, since I weigh less?”

“No, less for you.”

Emma frowned. “That’s not fair.”

“Maybe not,” I said, “but here’s the good news. Sex burns more calories per minute than climbing stairs. Way more.”

Emma thought about that for a second or two. “Next time,” she said, “let’s skip the stairs and go straight to the fucking.”