Responses
Sorry for being serious, but I think it's more about the idea of pairing the touching of the scar with pleasure that will turn the scar into an erogenous zone. When you do it repeatedly, you will basically "Pavlov"-ed yourself into thinking touching the scar = horny, hence it becoming an erogenous zone. It's just association (=・ω・=)
when the seme said that scars is an erogenous zone, I immediately touched my big scars at my belly from my surgery and can most definitely say 100% that seme is absolutely bullshiting.