The singer, 54, was asked who she'd like to to choose for the stunt, to raise cash for breast cancer research, on the Ellen DeGeneres show.
'I don't really have to think about it. My son is here here and I want him in that tank,' she said.
Madge told 12-year-old Rocco, whose dad is film director Guy Ritchie: 'You might never get wet, baby. I kind of suck at throwing.'
The pop queen failed to aim correctly in her attempt to splash Rocco, prompting Ellen to step in.
Rocco, who dances on stage during his mum's tour, told the audience that Madonna was 'a very good mother, but she's very strict' and asked what he thinks when she flashes herself on stage, he said: 'I actually don't see that.'
The stunt raised 10,000 dollars for the fight against breast cancer.
From Press Association Via Yahoo! News