The act of sneaking contraband in to jail by shoving it up your anus/vagina and tightening up your rectal/vaginal muscles
He was caught clenching some cocaine by the guards while being searched
Kaeya was a man of honor and pride, he hated being wrong and hated admiting defeat….thats why that night he was clenching harder than ever
Kaeya was clenching his Kaeyussy