Sero tied some mistletoe around his belt loop, so he could make some stupid jokes. His friends convinced Midoriya to give him a kiss, just under the mistletoe.
Uraraka even got Todoroki to record it, so they could tease him about it later.

While the Bakusquad was on the couch, Midoriya quietly snuck around them and crawled between his legs. The sight was enough to get Sero's full attention. His lips puckered up, while he moved in closer. Soon he met with his crotch, leaving a small smooch. Sero went bright red

obviously not expecting someone to go down and kiss him there. Kaminari and Kirishima started cackling, while Bakugo left as quickly as he could. He didn't need to watch what might happen.

A hand went to cover his face, while he tried to cover his embarrassment.

"You can't leave this unfinished Midoriya." Mina started to tease him, motioning to the growing lump.
Both the other males started chanting to blow him. His fingers went to undo his pants, letting his dick out. Sero grabbed the mistletoe and hung it over the

head of his cock. It didn't take him long to start kissing the head, big eyes looking up at Sero.
Once his tongue was tracing all over the shaft, while trying to stay along the largest vein.

Mina was watching closely and she pushed his head down, forcing him to start sucking.

"Come on Midoriya! Put some real effort into it." She was doing her best to encourage him, while he gagged on Sero's cock.
Her hand kept his head down, until he was able to relax himself.
Sero couldn't even hold the little plastic leaf anymore, letting it fall off to the side.

Every second in Midoriya's mouth felt like pure bliss and it didn't take long for the sexually frustrated male to cum. He did pull out, not wanting to make him swallow. Instead most of it ended up in his own lap, some getting around Midoriya's mouth.