Hard only when about to cum

I don’t know what the problem is but I get hard when I’m about to finish which isn’t the best for sex for example I’m receiving a blowjob until I’m hard but I’m on the edge of cumming so I don’t have time to enjoy sex any tips to help me out pls

Same here. I try to slow it down in my head and just spread out the sensation so I don’t cum but it’s a fine line