07/25/2007 at 11:00 AM EDT
Skivvy-dipping, soiling an expensive outfit and sailing with her sons sans lifejackets – it was a wet n' wild week for Britney Spears
And this time, PEOPLE reports in its new issue (on sale Friday), her antics could have some serious consequences.
On July 18 the pop star, 25, and her unidentified blonde gal pal stopped off in Malibu for an impromptu afternoon dip
(with Spears wearing only her skivvies!) before a crowd of photographers.
Her erratic behavior continued the next day when, after filming a new video
(self-funded, according to a source), she reportedly had a "meltdown" during an ill-fated photo shoot for Ok! Magazine
In the course of the session she apparently fretted that the ceiling might cave in, she allowed her newly acquired puppy to soil the floor and she wiped her hands on a couture gown after scarfing down fried chicken.
Finally, on July 20, Spears drew another wave of criticism for going boating with sons Sean Preston, 22 months, and Jayden James, 10 months – without life jackets. (Turns out they're not required by state law on such a large craft.)
Spears, who has no manager or personal publicist and has been without her BFF Alli Sims lately, "won't listen to anybody," says a family friend. "[Her family] is frustrated with the situation – and worried about the children."
Also worried, it seems, is their dad, Kevin Federline. The would-be rapper thinks his ex is exposing the boys to "unnecessary risk," says a source familiar with the case. "His lawyer [Mark Vincent Kaplan] hopes to get Kevin primary custody – soon."