Kourtney Kardashian welcomed her second baby, daughter Penelope, just eight weeks ago, but Scott Disick's girlfriend says she's always thinking about expanding her family.

"How many children do you think we could fit in this house?" a then-pregnant Kardashian, 33, asks her boyfriend of five years, 29, on Sunday's Keeping Up With the Kardasians. "In the playroom, I could build bunk beds for four."

Already dad to their son Mason, 2, Disick bristles at the idea of chasing six little ones around the house. "I don't want to be outnumbered by my children!" he yelps during the conversation with his girlfriend and her sister Khloe Kardashian.

"I need to see what it's like when I have two, but [having kids] is what life is about," Kardashian reasons. "I'm not going on the pill [after giving birth to Penelope]. I don't believe in it anymore!"

Though Kardashian is dreaming big as far as a family goes, she and Disick are relishing in second-time parenthood with Mason and their newborn. "Nothing could prepare me for how hard I fell in love with her," Kardashian raves to Us Weekly of Penelope. "With Mason, we have such a love affair that I never knew existed. I didn't expect it to happen again. It's such a magical feeling."

Keeping Up With the Kardashians airs Sunday at 9 p.m. (EST) on E!