Have you heard of anybody who can't have clitoral orgasm when her legs are wide apart, only when her legs are together laying straight down and lying on her back? Please help me understand.

Yes, I have heard of this and when you read the following three reasons you will see that indeed you do not have a 'problem'. Rather, like many women this is merely how you physically need to be positioned to have orgasms occur for you.

Porn Films Be Damned
Porn presented positions are, sadly, great for the camera's angle yet invariably completely hopeless for a woman's enjoyment.

Finding Your Most Sensitive Area
Physiologically, when a woman's legs are closer together there are more of the most sensitive bits in a localized area. She or her partner need not move too far to find the most sensitive area.

Muscular Tension
Some women require a form of muscular tension in order to expand their sexual enjoyment and orgasm, and this can only be achieved when they are on their backs with tight thigh contraction. After all your thigh muscles are some of the largest in your body.

How You Learned to Orgasm
Possibly the most influential reason is if this position is the one in which you first experienced and learned to orgasm via masturbation, then as with most people.

The way or position you first 'learned' is often one of the easiest and simplest routes to satisfaction.

What percentage of women ejaculate?
The percentage according to Dr. Santa Maria Cabello, one of the world's foremost researchers in female ejaculation, is that 70% of all women experience ejaculation.

What color is the fluid and where does it come from?
Those who have seen and/or experienced it have related to me the fluid 'was clear' to 'milky', and it tasted "buttery" to lightly sweet". The fluid comes from the para (meaning on the side) uretheral glands. And it is not urine.

Are there different types of ejaculation from G-spot vs. clitoral orgasm?
The ejaculation each woman experiences is very unique. Some women experience it as a result of the arousal with kissing, some with oral sex, some from G-spot stimulation and some from heavy petting. Again it is uniquely personal to each woman.

Dr. Megan Fleming discusses what women need in order for her to reach orgasm. (via HowCast)