Making a baby imitating dad and mom

"It's unfair to do something so pleasant with mom and dad!!" "Why is it not okay? You're just playing with your big brother?" "What's Kikenbi? What's dangerous?" "...It looks like fun...I want to do it too, big brother..." "My dad's penis is getting bigger... why are you big brother?" "You're licking your penis? Is it delicious?" "Putting your big penis into your crotch hole...it feels really good...you want to try it, don't you?"