My sexuality works totally differently when I masturbate compared to when I have sex. Having sex, I like a lot of penetration and not much clit stimulation, and I have multiple orgasms fairly quickly. Masturbating, I rub my clit, take quite a few minutes, come once, and fall asleep. Even if I stay awake, I have absolutely no desire to continue after the first orgasm, and it feels uncomfortable to try.
The weird thing is, although I know I've joked about it a few posts back, I actually can't watch porn and masturbate. Nor can I use a large dildo or buttplug. If I do, I come instantly and can't go on. Setting myself all up for a nice fancy masturbation--moving the computer monitor next to the bed, getting out and lubing the best toys, getting into a really fantastically horny mood--always ends in thirty seconds of disappointment. I'm a premature ejaculator. (Not literally.)
So when I'm alone I use only my hand, and only my imagination, because it's the only way to get more than an instant of enjoyment out of it.
When I'm with a partner I go "prematurely" too, but unlike when I'm alone, I can do it again. And again...