Hank Baskett IV sure is a big bundle of joy!

The first son to Kendra Wilksinson and hubby Hank Baskett was born Dec. 11, weighing a healthy 9 lbs 5 oz.

Less than a month later, his Mommy reports that he's growing up fast. "Hank is such a BIG kid," she Tweeted Wednesday, presumably while shooting her E! reality series Kendra. "he stole the producers walkie talkie n talkin sh** to the crew lol."

Earlier in the day, the new mom, 24, marveled at Hank's precociousness in, ahem, another area. "lil man just had an atomic poo. lol," Wilkinson wrote. "how can something so small let out so much poop."

She adds to anyone put off by the baby-poop talk, "the saying "TMI" SUCKKKSSS sooo bad! hahahahaa"