sperm viscosity?? and cum TMI

Julie • Pregnant with our rainbow baby! 🤰🏻🌈🥰
My fiancé normally has thinner cum when he ejaculates; occasionally it's really thick. What kind of viscosity of cum is best when TTC? Usually it's white but thinner than I've seen before; it sometimes is a fainter white when it's thinner consistency, and more obvious white when thicker. Also when he does orgasm he has to "push" it out to cum. He doesn't just cum during, he has to push out the cum every time we have sex. He feels the orgasm getting close then has to "push". This is how he almost has multiple orgasms. Is he not letting it all out the first time and that's why he can cum again a bit later(still having sex between orgasms) Is this normal?