so... my 12 year old nephew gets baby'd 24/7 and I refuse to baby him... so when he comes in and starts hugging on me…

so... my 12 year old nephew gets baby'd 24/7 and I refuse to baby him... so when he comes in and starts hugging on me and laying on me I tell him that he needs to get out of my space.. well then I get yelled at for being mean to him.. is there a nice way to say "get off of me you're 12 and I am already carrying a kid here.."????