It means “the nipple reacts to touch” in Portuguese. More naturally in English, it can mean that the nipple becomes sensitive, stiffens, or responds when touched.

In plain language

  • Mamilo = nipple.
  • Reage ao toque = reacts to touch.
  • In context, people usually mean the area is sensitive to touch or that the nipple gets erect when stimulated.

Possible nuance

This phrase can be neutral and medical, but in some contexts it can also refer to sexual arousal , because nipple stimulation can trigger a physical response. The exact meaning depends on where you saw it.

Example

  • Portuguese: “O mamilo reage ao toque.”
  • English: “The nipple reacts to touch.”

TL;DR: It means the nipple responds when touched, often by becoming sensitive or erect.