What is the context of this Superman comic panel in which Luthor is saying "Yes, sir" to address Superman?

Question

I asked this question where a user posted an answer containing this -

So what is the context of this and why is Luthor calling Supes "sir"?

I did ask in the comments section for the context but @Clockwork suggested me to ask a full question instead.

Answer 1

Those panels are from Superman Vol. 1 #282.

Lex Luthor de-ages Superman by a decade in order to rob him of his experience and memory. While a jet-hijacking distracts Superboy, Luthor dons his new green and purple Battle Array costume. Using his sophisticated weaponry, Luthor sends Superboy on a collision course with the centre of the planet; but when he moves in to scalp Superboy with a laser — Luthor plunges down with him. To escape, he's forced to reverse the de-aging of Superman. Wrapped in Superman's cape, Lex is dragged from the Earth's core and out an undersea volcano; straight to prison.

In the main story -- titled "Lex Luthor — Super Scalp-Hunter!" -- Luthor attacked Superman with a variety of weapons, with the ultimate goal of scalping him, as he blamed Superman for the loss of his own hair.

One of the weapons he used caused Superman to de-age by ten years, making him less mature and more impulsive, and another weapon caused Superman's weight to rapidly increase, to the point where he couldn't stop himself falling toward the Earth's core. However, Superman pointed out that since Luthor was directly on top of him as he was falling, he too would be dragged down by the combined gravitational pull of Superman's body and the Earth's core, and Luthor realised that the high temperatures at the Earth's core would kill him.

He concluded that the only way he could survive was by giving Superman pills that would return him to his normal age and maturity level, so that he could think of a way to get the both of them out of that predicament. As such, Luthor's life was in Superman's hands, and he was evidently willing to take orders from Superman and address him as he would a superior, until his life was no longer in jeopardy.

SUPERMAN: I'm getting heavier all the time--and the heavier I get, the closer to the Earth's center we sink! I'm now almost as heavy as the planet itself...you can't escape the combined gravity of me and the center of the Earth!

LEX LUTHOR: You're right...and there's no way I can reverse the process! We'll both drop toward the center of the Earth...until I burn up from the heat of the Earth's core! Superman--get us out of here!!

SUPERMAN: I--can't think straight--can't think how to get us out! You've finally beaten me, Luthor!

LEX LUTHOR: No!--No!! Don't give up! Superman never quits! Look--I'll give you these pills to make you normal again! Then you'll be able to figure a way out of this--you always do! Here--the pills should work immediately!

SUPERMAN: Yes--I feel myself aging--getting back to my old self...beginning to think more clearly! Just give me a moment to concentrate... Luthor, here are your orders! Pull off my cape and wrap yourself in it to protect yourself! It detaches from two hooks inside my shirt!

LEX LUTHOR: Yes, sir--anything you say!

_{Superman Vol. 1 #282 (December, 1974)}