This is the perspective from a guy: if you/he are young and relatively inexperienced it could just be nerves. This happens and will prevent or delay ejaculation from oral or sex. Did your relationship progress to sex yet? Still the same issue? This is important as it it is still there then it's probably just performance anxiety due to the brain not knowing how to distinguish from fear and excitement. Fear and excitement actually cause very similar reactions in the body if you think about it, raise heart rate, sweat, tensing of muscles (and lots more). I'd say if it's this, it'll change in time. However, if ejaculation with sex is not a problem, or in the event you didn't get that far yet, you might want to consider a change in technique. That shaking or tensing of the legs you described could also be due to too much stimulation or pressure. We can kinda go a little numb sometimes. When masterbating, guys with foreskin wouldn't often touch the head much. If they did, or those without foreskin, they would be likely using some sort of lubricant. If your sucking hard or using your hands on the head (saliva sometime just isnt enough lubrication) you could be desensitizing him. This results in a delay or inability to finish. So a softer more rhythmic approach could be better. The other consideration that I think is particularly important is what you do with your hands. Remember, he's been doing with his hands for years, so it's important that this aspect remains present. A soft but constant grip about half way down (and remember to tuck your thumb around your fingers, not to leave it along the shaft as it can actually be painful along the bottom edge). The other thing I'd say, and tbh it doesn't look easy... You kinda have to keep at that technique for some time. Sure, mix it up with different techniques in the first chunk of time, but if you feel he's actually getting close, and you've identified the right technique, you gotta keep doing exactly that technique. If it doesn't happen within a few minutes then slow it down, soften things a little, mix it up (take it out, you'll need a break), then return again to that technique. Finally... You mentioned about 69 somewhere in one of your posts. From an oral perspective, it's the holy grail if you love each other. However it can actually be quite a difficult position to get comfortable in. What do I do with my legs... Sideways or girl on top... Left or right side. Ask him what is more comfortable and try different positions out. I guess one of the main reasons I raised this is that hearing my girl *** is one of the best feelings and whether we're in 69 or having sex it will often make me *** with her. Is he hard after pleasuring you? If so, this turns him on and he may be worried that you're not getting pleasure by giving him oral. While the technique is more challenging 69 could be the way to set that fear at ease for him.Best of luck. As a guy, finding a girl that wants to do this and do this well really does end up being some of the best orgasm's ever experienced. I'm sure you guys will get there.