It was Zac’s birthday. Any excuse to fuck my boy is a good excuse, and he enjoys it as much as I do. Of course, that wasn’t the only present he got. I would get my pride and joy anything he wanted, if I could. I couldn’t resist giving him a birthday spanking, as well. Bare-assed, of course. Over my lap. Cute butt on full display, all for his dad. Just like old times, except not really. This was a father’s duty. This is a dad’s pleasure. I’m an old-fashioned dad. Corporal punishment was not an everyday thing. Spankings were reserved for serious infractions, but I don’t see anything wrong with a hand applied firmly to a rear end when a lesson needs to be deeply ingrained. Of course, that ended at a certain age, when he was fully old enough to understand his mistakes on an intellectual level. And the threat of being grounded was a serious consequence. However, there is no expiration date on birthday spankings. Truth is, he hasn't had a birthday spanking in quite a while. I don’t even know why it popped into my head to tell him to bend over my lap. It was like a blast from the past, but I was looking down at a young man’s firm round ass. One that I’ve fucked on many occasions. It was one of those moments when I’m reminded that I sired Zac. Fucked him into his mother with the same cum I fuck into his hole now. Then I spent years raising him up to be a fine young man, never imagining that young man would also become my lover.As I started to spank him, I was overcome with a mix of paternalism and dominant Daddy. My sweet boy. My tight fuck hole. My dick, hard as a steel pole in my pants, poking into his belly as I brought my hand down hard, making him squirm. I almost surprised myself with the force of that first swat, but he barely whimpered, so I kept going, getting more turned on with every smack. He raised his ass, his cheeks parted for just a second, and his hole winked at me. I couldn’t resist it.I drooled spit onto my boy’s rosebud before sliding a finger deep into the warm velvet channel that it guarded. A gate that I unlocked months ago, forcing my fat cock head past its resistance, diving in deep where no man had gone before. As far as I’m aware, I’m still the only man that has been there, and I go back to every chance I get. If a spanking barely made Zac whimper, two fat fingers sure did, but that was just teasing him for what was to come.Of course, he knew where all of this was headed when I told him to take his pants off. He was probably just wondering when I would get tired of spanking him and fuck him. That didn’t take long at all once I had my fingers in his hole. I told him to get on the bed. Like a good boy, he assumed the position, on all fours, legs spread wide, back arched to show me his hole.I had my clothes off in record time, crawling up on the bed, my mouth already watering and my tongue tingling as I dove face-first into his sweet ass. I wanted him opened up and horny enough to beg for it, before I fucked him. I’m pretty well hung, and I know it hurts going in. He needs to want it. Of course, it’s an appetizer, for me, too. Licking and kissing, slipping my tongue between his lips, knowing my cock will be there too, in just a minute. Diving in much deeper than my tongue could ever go.As I crawled up on the bed beside him, spread his legs, and started to give him his birthday present, a funny thought occurred to me. Now he knows what it was like when he was younger and always bought me a box of his favorite candy for Father’s Day, because he knew he would get to eat half of it.