My brother keeps farting on me, what can i do about this?

Hi, i have this real issue, my brother who is 4 years older than me keeps farting on me, not constantly, obviously. Like when im eating my dinner, he would sneak up on me and fart either in my face or on my dinner. When im sleeping he would fart on my face when im dozing off. What can i do to stop this? its really disgusting and annoying to me. A few times ive cried afterwards. I told my parents but they dont take me seriously. Any advice would be welcome, only good advice.