Fibilance

Fibilants are fricative consonants of medium to low amplitude and pitch, made by directing a stream of air passing through the teeth

It's is a language device, similar to sibilance, however it connotes a different meaning in a different way. Sibilance mostly focuses on the sound itself produced, whereas fibilance mostly focuses on the facial movements from the readers to convey emotion

Person 1 - "This author uses many 'f's' in this sentence, what could the language device be?"
Person 2 - "It's fibilance"

Jaylan

The only person who is likely to be in top set P.E at school.

Person 1: "wow Jaylan says he's not in top set P.E"
Person 2: "That's definitely a lie, he's in top set P.E no matter what"