My understanding is injury/surgery caused his nerves to get a bit mixed but and now his body made it a very sensitive erogoneous zone
this story is exaggerating as a plot device but most people have them. injury or surgery can make a zone but they can happen without trauma. in reality one random touch is probably not going to result in an instant boner. they are just another spot to use for foreplay and to get into the mood. common places can be ears, feet, necks, armpits(shutline shoutout), lower backs, but anywhere really. this part of the reason thorough foreplay is so important, one could be missing out.
hopefully not tmi, but personally my non obvious erogenous zone can get me going better then the obvious ones.
Bro how? How do you get horny but touching your shoulder?? Genuinely can this happen in real life?? Anyways I ain’t gonna judge cuz I’ve read wayyyy worst