For guys/tops: Pace yourself, learn some foreplay techniques that can keep your partner aroused when you need to break or slow down, and generally don’t allow yourself to go full bore until you think it’s a good time to cum. A lot of this is really just learning what your partner likes and enjoys, and experimenting to find different ways of doing things. Can they get off from their chest/nipples? Do they their butt being touched, groped, spanked or fingered? Is there a particular way you can grind against them, penetrate them or thrust that keeps you aroused but doesn’t stimulate you, but gets your partner closer to their next climax? If you feel like you’re going to blow too fast, suggest changing positions, use that break to clear your mind some and reset while your hands and mouth keep your partner stimulate and your dick gets a bit of a break.

Outside of sex with a partner, you can edge/tease yourself to improve your sexual stamina somewhat. If you’re jerking off, don’t get yourself to cum soon as possible, but build up a rhythm and take semi frequent breaks. Staying hydrated and exercising regularly also did wonders for my bedroom stamina.