How do I last longer?

During oral sex with my boyfriend, I usually get really tired within 10 to 15 minutes, it really becomes an issue when I’m on my period and i want to give him a treat. Or simply when i just want pleasure him. I made him cum once by just sucking him off and that time it took so long (i kept pausing) and i felt like he kind of just forced himself to cum faster because he wanted it to finally be over. Any tips or advice? How the hell do i last long enough to make him cum WITHOUT taking so long?