please help i’m losing sleep because of my chin

i got a new chinchilla named Mochi about 3 weeks ago. the place i got him at said he was about 6 months to 1 year. at first he was really skittish but only for a few days. he already lets me scratch his chin and under his ears BUT he is so persistent! he does not take any firm “no’s”, light “pushing” to try and sweep out his cage, or blowing which someone on this site suggested. if i do any of those, he stops for .3 seconds and keeps going. he’s also CRAZY about humping my arm. he’s got lots...

please help i’m losing sleep because of my chin