Riding tips

I dont know if anyone has seen that gif on twitter of a pig in a kitty pool and the caption is "me trying to spell coconut" but that's literally me when I try and ride my boyfriend.

So my boyfriend is usually the one doing all the work. I help out too but I never really ride him, mostly because I feel like I'm not doing a good job and I get tired. I'm on the chunky side so I also am kind of insecure about it but I really do wanna be on top and I wanna get better at it so I just was wondering if theres any tips anyone has or any specific tips for bigger girls.

Also, there are times where he wants me to ride him reverse cowgirl but again I struggle with that haha mostly finding a comfortable way to do it but any tips on that specific position would be great ! thank you!