Singer Christina Aguilera came off as sexually wild at her recent Sydney concert compared to the subsequent tame offerings of another pop diva, Gwen Stefani.

Aguilera's performance at Acer Arena last week was punctuated by a faux dominatrix skit with a male fan tied to a circus wheel. The heat was turned up when large-screen sepia-toned videos were shown of her romping semi-clothed and nude, the Sydney Daily Telegraph reported Wednesday.

The suggestive flavor of the concert prompted the departure of at least some families with younger children in tow, the newspaper said.

If Aguilar's concert could be considered soft porn by some, Stefani's performance a week later was practically sedate. Stefani said she was surprised to see so many young children at her concert.

"During my tour in America, it was surreal to see how young the audience was and I didn't expect it," she said. "We're talking about 5-year-olds and 8-years-olds and a lot of them. There's something so fun about that because the pressure goes off you a bit. You just go out there and have fun."