How can I sneek my laptop?

I'm going camping with a friend of mine and I don't want any body using my laptop while I'm gone and he said that he doesn't want me to bring and he made up all these excuses like it's take up to much space and I know your going to use it but I told him that I wouldn't and I really won't. I put a password on it but if one of my siblings gets a hold of it and tries the password a whole bunch of times to will erase the data on my laptop. please help. if it helps we're camping in a camper. don't know how big though.