idk man

Donovan: Weak, I sleep with a gun under my pillow

Sherlock: You both are pathetic

Donovan: Oh yeah? What killer weapon do you sleep with, freak?

John: Rosie did Sherly pick you up early from school?

Rosie: No.

Sherlock: See? Case closed.

Rosie: We didn't go.

John: Case open.

Rosie: We went shopping.

Sherlock: Ha ha, shush now, Ros-

Rosie: Papa bought us matching coats. Look, look!

Sherlock: Rosie go to your room.

Sherlock: It's okay, he is not a real horse it's a cartoon

John: Horse? A Horse???

Sherlock: In my defense I've never seen it

Sherlock: He injured his wirst

Mycroft: Well I got stabbed in the leg

Mycroft: *stares at Greg in disbelief*

Sherlock: Yet you're talking.

Greg: ...but I agree with Sherlock.

When they go to bed John turns off the lights because he doesn't want Sherlock to see his scar, he thinks it is messy, making him feel sad, angry, and ugly. Sherlock, being the baby insecure boy we know he actually is, thinks that John doesn't want to see him while they are having sex (He is Mr. I-Am-Not-Gay after all).

Maybe Sherlock points this fact out or John simply notices something is wrong and asks Sherlock. John explains the actual issue, he doesn't want to be weak in front of Sherlock but he doesn't want Sherlock to feel unattractive and not loved.

Sherlock turns on the lights and starts showing John all the scars on his body, telling him how he got them. Then, while kissing and caressing John's scar, Sherlock says that he maybe is being selfish but he loves all of his and John's scars because they made them who they are, and they are amazing, spectacular, fantastic, and in love. They made them the detective and the doctor.

Sherlock: Well, maybe what's in my pants will change your mind.

John: *turns around*

Sherlock: It's a list of cases that came to me by email

Greg *looks at Mycroft up and down*: Yes.