Too touchy toddler

Our toddler 3 1/2 years old, out of comfort has a habit of putting her hands down my shirt, sometimes her grandmother’s and her father’s shirt. She’s been doing that since she was an infant while nursing. However, sometimes I feel over touched and don’t want that, she gets aggressive and tries to shove her hands down my shirt, it turns into a tantrum. And once she’s calm I explain to her she can’t be touching other people if they don’t want to be touched.

So I noticed today, she’s starting to put her own hands under her shirt. I don’t know what to think, do I stop it? Is it just a phase?