You Completed the Caption

 It seems this cartoon is popular, and some of you have already seem it. Nevertheless...

LT: Seriously Dad! If your going to give Mom a spanking, do it the correct way! Since you're right handed, Mom should be facing the other way across your knee! Everyone knows that! 

KDPierre: I remember when this card came out! In fact I still have it in my collection. Anyway, this one is ripe for SO MANY possibilities. It's just a matter of how far down the rabbit hole you wish to descend. LOL Here are a couple:

Relatively innocent
"Hey, you remember how you told me before how I couldn't get a new I-Phone? Well, when you two are done, I suggest we all take a nice trip to Best Buy, or by dinnertime everyone's gonna know what you two are into, starting with Gramma."

Not-so-innocent
"Yo, Pops. Hold up a minute. Let me get you the paddle Jimmy and I use when we play like that. It works great and really is easier on your hand."

Edgy
"Daaaaaa----ad, no fair! How come you never play like that with ME?"

Anon: Why does mom get to keep her panties on! Not fair!!!! 

Jeanie: "Dad, my boyfriend, Chad, in the fourth grade, says that you should never start a spanking before discussing a safeword. Do you and Mom have one? May I suggest the "red, yellow, and green light" system? It gives everyone a clear idea of how things are going... Chad also says that a proper spanking doesn't start until the panties are pulled down. I've been listening from my bedroom, and you two have been playing for about ten minutes, but Mom's still wearing her underwear. When are those knickers coming off? And are you sure that using just your hand will get the job done? Most submissives love seeing marks after a thrashing. May I suggest you use your belt, Daddy-dear? The last time Chad used his belt on my bottom was so hot; I was bruised for days! Of course, Mom prefers using the wooden spoon when paddling me. It stings like the dickens, let me tell you!

Brett: "Dad, stop! There are many discipline strategies that are more effective than corporal punishment. Violence is not the answer." 

Prefectdt: I'm trying to sleep! If you two don't keep the noise down, you're both up for a time-out.

Wendel: I have this one in my collection, but I will make up something else.
“Like you always say when you spank me: This is gonna hurt you more than it hurts me.”

Tankerton Latch: "The spanking Daddy's giving you now, Auntie Jill, is nothing compared to then one you'll get if Mom catches you!" 

That was fun! Please stay for brunch. It's almost ready.