Carrie Underwood has released a hilarious holiday song that celebrates the need for "stretchy pants'' after eating a big meal - and it's all for charity.MORE: Brad Paisley's wife Kimberley shares hilarious picture of country star as they celebrate special momentThe star has teamed up with Brad Paisley and The Store, a free referral-based grocery store in Nashville that aims to help people lift themselves out of food insecurity.WATCH: Carrie Underwood and Jimmie Allen discuss 2021 CMAs"I’ve got a