sexual assault or no?

my uncle use to grab my butt all time smack it. everytime i seen him one time he took naked photos of me when gettin ready i never told anyone but my bf... and i hate when my bf smacks my butt it reminds me of what use happen to me everyday.... he use to take his penis out in front of me and my sister. my sister knew about it to... when he around my grandma i make sure my daughter is safe wnen im visiting it makes me sick thinking about it.... he also use to hump the floor in front of me it was disgusting... this happened when inwas younger like 15 and up... till i left rna away...