My Dog is constantly smelling her behind

My dog is a Jack Russel/Chihuahua mix. Will be 2 years old in a few months. She is always smelling her butt after every single thing. I pet her, she smells her butt. She’s laying down and decides to get up, she smells her butt, I’m talking to her, she smells her butt, I let her outside to go potty, she smells her butt, she comes back inside the house, she smells her butt, she’s laying underneath the blanket and decides to get out, she smells her butt. Sometimes she’ll be sitting down and she’ll turn her head to smell her butt but she can’t cause there’s not enough room to turn. It’s gotten to the point now that it’s annoying and irritating to see. If I see her doing it, I tell her no and she’ll stop or she’ll run to somewhere and smell her butt. She just loves smelling her own butt. I know dogs do it so they can get their scent but my dog does it way too much, every single thing she does, she smells her butt. I just want her to stop being such a butt sniffer.