This whole situation was a lot to think about. The more you thought about it, the more troubled you felt. "Might as well get to bed and try to not think about it" you said to yourself. Luckily, you had decided that your mother, who otherwise shared a bed with your father before all this, was going to sleep on the couch the first few nights until you could decide what to do with the sleeping arrangements.
Turned out getting to sleep would be easier said than done, feeling the weight of your fathers body shift across the bed a foreign feeling. Everything feeling... wrong. But eventually, you drifted off to sleep.
You awoke in the middle of the night, in a sweat. First thing you did was reaching down to feel your body, hoping it was all a dream. But it wasn't. Your new hands reached down to feel your new larger gut. Your hairy gut. But that wasn't the worst part. The part where you were in the body of your own dad. No, The worst part was that you had just had an erotic dream. Your father's erect penis poking up through your pajamas being something you were not ready for.
But yet, something made you reach down for your new equipment. You hadn't looked to closely at it in the shower prior - but you noticed that you had gained quite a lot of girth from your non-erect state. And probably a good 2-3 inches at that. "Damn, I'm pretty big" you said. "Wait, did I just refer to this thing as mine?" You thought. But instead of pondering the implications of what you just had said you kept feeling your new penis. Your erotic dream had gotten you into a state of mind you simply wasn't ready for in this body - and soon you were stroking your new cock while thinking about the person you had dreamt about - your now former teacher. She was probably around the age of your father and quite attractive. You hadn't really thought to much about her before, but you wondered if maybe being in your father's body had changed your tastes a bit. A thought you soon tried to dismiss. You were now pumping your cock with quite the determination. You couldn't help but get turned on by the fact your shaft was now larger and thicker then it been just a few days ago. Lost in enough pleasure to not think about how weird this was, or that the new thick dick between your legs was your fathers. "Damn, I want to cum" you whispered. Now furiously wanking your penis. You started fantasizing about your teachers fat behind bouncing up and down on your dick. Pressing against your big belly with every bounce. Not yet realizing you were already using your father's body as a stand in for you in your fantasy.
After what felt like eternity, but was probably something like fifteen minutes, you erupted. Hot white liquid shooting out of your father's... No! Your cock! Something had snapped during your masturbation session. Maybe the implications of what you had done was easier to deal with if you told yourself it was perfectly normal. You were just a man that had just pleasured himself. Nothing wrong with that. Even if the body you were in wasn't your own originally. It was yours right now. "Exactly" you muttered to yourself. "This is my body for now... This is fine. Totally fine..."
You went into the bathroom to clean yourself up. Coming into the bathroom, seeing your father standing there in the mirror, with jizz on his hairy gut made you start realizing what you just had done. This was all so wrong. But yet - this was inevitable. At least you told yourself that. At least three years, most likely forever, this was your body. You were going to want to enjoy yourself. Maybe it was for the best that it already happened.
You started to wonder what your dad was doing inside his new body. Had he also enjoyed himself? After all, he was young again. Your father was probably looking forward to growing a little bigger and then getting with girls your... his age. This was all very confusing. Hell, in a few years he might bring back home a new girlfriend. Even thought it's perfectly normal he and mom would have to move on, It would probably feel like a punch in the gut for both you and your mother. While you have to pretend you're two happy parents. Not a former son and former wife. You felt angry. For something that hasn't happened yet. Something that might not happen.
You didn't want to think any more about this. And instead went back to bed. Not that it fixed anything the first time. Falling asleep a lot faster this time.