claim (Patreon)

Katsuki has been observing Izuku being oblivious to to all the extras flirting with him and accidentally flirting back and it's only a matter of time before the nerd lands a date and get his first kiss stolen by someone who is not Katsuki. Deku would want Kacchan to be his first. Katsuki is just preventing Deku from making a mistake. If he taints his lips first no one can steal this number one spot from him.

(in which Kats is a lot more yandere than usual X3)