Man eating shark. Baby talking to Aquarius man. Baby-talking to Aquarius man.
I assume the querent is an adult who wants to coo over her boyfriend. Well, good luck. I cannot think of a sign less susceptible to baby-talk than Aquarius. Now, Cancer … a Crab could get into that, since he wants to be mommied anyway. Cancer is ruled by the Moon, and the Moon governs the mother-child interaction. But Aquarius is incompatible with Cancer in every way. Cancer is an emotional water sign, whereas Aquarius is a mental air sign. Aquarius is ruled by two planets: emotionally-detached Uranus and cold, hard Saturn. Other planets in his chart notwithstanding, I just don’t see how an Aquarius can melt over “baby baby” and “my wittle water-beawah.” He’ll just look at you funny.
Air signs are just not that emotional, and Aquarius is probably the least. Venus-ruled Libra could probably get off on baby-talk because he’s relationship-oriented, and virtually anything that can enhance your bond is fair game, as long as the game is fair. And Gemini … well, Gemini is a little kid, anyway. Gemini is ruled by Mercury, and Mercury governs communication, so you can’t go wrong there.
So “goo goo” over someone else, would you?