What if I associate oral sex with promiscuous behavior? What's being hidden is, in part, all that which is intimate.
Freud doesn't speak directly much about it.
Have them sit on the chair while you kneel before them and take matters into your mouth, or you do the sitting while they stand with their legs on either side of the chair while you lean in.
My close friend and her husband have a age gap of 17 years, her being older.