Sano Manjiro, nicknamed Mikey, he was your boyfriend, after a "fun" night, you and him were at the cafe with Draken and Takemichi.

Suddenly Takemichi looked at Mikey's neck, he saw many bite marks (also known as hickeys) and red marks like mosquito bites on his neck. When Takemichi asked Mikey, he blushed slightly as he chewed taiyaki and looked at you. Mikey answered in a slightly low voice, "It's just..'a mosquito' bite.."

And the mosquito he mentioned is you.