Double cheese entendre (with fries)

Mum and Dad stayed with us Friday and Saturday nights. On Saturday evening Sally and Matt came up for a big family dinner. Elf made fantastic lasagne. Marcus was objecting to it, so Sally decided to emphasise the positives. He likes cheese, he likes peas, so her approach was obvious. "Come on, its chock full of cheesy peaness!" The assembled family spluttered, squawked and snickered, while Sally went back over what she'd said in her head to work out why it was so funny.