Brother and his girlfriend problems! HELP ME NOW PLZ ! POINTS TO BEST ANSWERS?

Ok so first I am sitting in myliving room and my brother and his girlfriend wont leave and they are ontop eachother and my bros rubbing her *** and they are full on making out and it is seriously pissing me off. Everyone comesup to me at school and is like ok you need to talk to your LITTLE brother and tell him to stop making out in front of the school. and every one is like it's not even kissing it's like eating eachothers faces. And I don't want to leave because there 13 and having and Iwant them to stop and not give them the sacticfaction. HELP ME WHAT DO I DO?!?!?!?!?!