My siblings constantly talk badly about me

Family…sorry for the long post I’ll make it short as possible. Basically we are normally quite a close family. But the siblings dig at me when we are all out. I ain’t allways perfect but I admit it for sure when I ain’t (I’m quite a straight person) But our parent likes us all together when we do things but it’s making me feel sad doing it but I have to ‘keep quite’ to keep them happy to have us all around at same time. They team up and try make me look the bad person for reacting back. Well we was out and I simply was talking to parent and then they start doing shitty digs for me to hear. I didn’t say anything bad to them or about them was actually talking about paying for a treat to the parent. They got all funny about it, and because I said no need be an arse hole I’m the bad person. They do this on many occasions. Then they try making me out to be the bad person because I snapped but why should I keep putting up with it. Parent now uptight because we won’t be together all at the same time. now makes me feel bad. I’m type person to help out whenever I can but fed up of keep taking the rubbish to make parent feel happy. My happiness should count to right? Why should I have to keep taking it when we are out to please 1 person and then feel crap for the rest of the time? Don’t get me wrong they can be nice when their being ‘pleased’ or its ‘their way’. I don’t really no what I want out of this really. Maybe just to see if u people think I’m wrong for saying something or just keep my mouth shut to please everyone like normal. Just brings me down feeling trapped having to watch what I say and do knowing they can start with the way they act at any time. Parent feels in the middle as we won’t be alltogether but why should I be made to feel like that. Am I putting parent in the middle by going out separate? Plenty of days in the week right? Why can’t we all just see parent at diffrent times and my happiness count. I just want to feel like I mean something right now