One day Genos came waltzing through the door with two pieces of bread.
Saitama didn't really know why. Until Genos stuck one on each side of his face and yelled "What kind of sandwich are you?!?!?!"
Now if you know anything about Genos, for one he never yells at his sensei unless said sensie is in "danger" (which at his current point in life is Genos lack of self care is the only things that's about killed him). Secondly Genos never waltzes anywhere so Saitama knew something was up.
Saitama knew what this was from the he's seen the funny "what kind of sanwhich are you" - " An idiot sandwich" thingy.
So in a moment of brilliance he said "I am an egg sandwich!!!"
Also if Saitama was being completely honest he's never seen Genos laugh so hard in their time together. (Saitama vowed he would make him laugh again)
ᗩ ᑕOᑌᑭᒪE ᗪᗩYᔕ ᒪᗩTEᖇ (cool font lol)
Genos was alone in the apartment surprisingly. While he was busy with Hero's Association there was a sale so Saitama went by himself.
"He should be coming soon," Genos thought.
After a little while though his sensei was still not home but as he started worrying he heard several thunks outside the door.
Once he opened the door he was attacked by bread? One piece in each of his checks with his sensei standing a close face almost touching Genos chest.
Genos started steaming.
Then Saitama asked him loudly, "What kind of sandwhich are you!?!?"
He didn't get it at first. He then realized he had to correct his sensei so he said, "I'm not a sandwhich, I'm a toaster!"
Saitama collapsed against Genos laughing while his pupil desperately tried to keep him from hitting the ground. Genos couldn't help himself and started laughing as well thinking "Sensies adorable."
"You said that out loud dude." (Saitama)
"You're adorable too."
-A little bit later & they are watching TV-
"Dude did you bring the groceries in" (Saitama)