ejacgloatation

Extreme, forceful gloating. As if one was shooting boastful comments at one's audience / the target of ones gloat.

Often combined with "premature" when someone is excessively boastful prior to the event.

premature ejacgloatation: My insert sports team is gonna kick your insert opposing sports team's butt so hard tomorrow, they won't be able to sit for a week.

Or,

I'm so intelligent, I'll do way better in my exams than anyone, I'm sure to get top marks in all of my subjects.