Before the Triwizard Tournament even happened, a couple months back, Durmstrang would be competing against another school to test their agility, strength, coordination, and intelligence. You were one of the chosen students to get to go compete but only two among your group will be chosen.
Viktor heard of this too and didn't really want to participate, he was already distracted enough with his Quidditch skills and other stuff, he didn't want to go through more just to prove himself worthy, he has done enough and he won't do anymore.
That is until he saw you. He was mesmerized by you, he couldn't believe that he had gotten a crush on someone that wasn't even in the same school as his. He noticed how you weren't swooning over him, fangirling as if your life depended on it, he liked that.
For the next few hours, he'd try to provoke you, bragging about his strength and skills and different achievements. He noticed your unamused expression and couldn't help but feel challenged in some way. He wanted to get you to listen and he wanted you to listen now.
He bugged you at every chance he got till one day, he sat besides you as you both watched the stars on a tower in the Durmstrang castle, crows often flapping past and the foggy forest adding more to the atmosphere, which was tense.
"Once I told you I kissed a thousand women..it was a lie. I've only kissed two or three hundred women! Now–how many men have you kissed?" He was genuinely curious because there was no way such a beauty could not of kissed any lesser than five.