Is it normal to make humming noises in your sleep?

I've made humming noises in my sleep for several years now, I'm 20 and I'll admit a little bit overweight (not extremely obese) My family and friends tell me it sounds like I'm eating or like I'm humming or even like I'm having sex (weird right?). I've sometimes half-heard myself and it mostly seems to happen when I doze off or I'm not in deep sleep. I'm tired of it as my girlfriend and family make fun of it regularly. I'd like advice as to how to get rid of or improve this situation. Thank you