My question is about the best sex positions for a ...

The G-spot is located on the front wall of the Vagina, aprox. 2" inside. If penis curves to the left the best position would be lying on your right side, and your partner on her left side. Put you left leg between her legs for an easy and comfortable penetration.

The position I've just described is one of the most positions I know, but many people just aren't aware of that.

Good Luck.  

In my experience, a lop-sided penis doesn't have any influence on sex - the vagina sort of directs it in the right way - there aren't that many options in there really....

What I found work best for me for g0point stimulation is (how boring...) the missionary position.

You should know however that there are several types of female orgasms and the G-point is just one of them, some women don't like the G-point stimuli at all, and some can have an orgasm from penetration when the shallow inner part of the vagina  is being touched for me the best way to get this orgasm is missionary position with my legs closed. 

It's very different from one woman to another and everybody likes things different - so I guess experimenting is the way ot get it right, especially with a new lover.

Studies showed that just about 30% of women have an orgasm in penetration, so again - the best thing to do with a new lover is experiment, and of course, ask. 

Try getting on top, but your back is to him.  My ex was curved to the left and this worked well for me. 

Add 1 or 2 pillows beneath the Females bottom, Lift legs & Place on Shoulders or Fold then back (Be sure she"s comforable) Get between her legs and enter her in an slightly upwards motion. ( you have to turn your penis to the right so it faces the 12 O'Clock position to reach her G-Spot)... Once you start Penetration go deep on the down stroke and withdraw slowly in the upward 12 O'Clock position She will let you know when you find it. Slow Roll her to a powerful Orgasm.

Woman on top works well for me and alot of women.There is direct clitoral stimulation,she controls the speed and depth,and she's in a position where you can stimulate her breasts which is great.Another good position to hit the G-spot is a take on missionary.The first time I did this it blew both our minds.I asked my boyfriend to thrust as deep as he could,then stay still.Then I planted my feet,tilted my pelvis and starting grinding up and down and in circular motions.It usually brought us both to climax within minutes and being face-to-face kicks the intimacy up a notch.My third favorite position is doggy,except I lay down on my stomach with a pillow under my hips so my butt is raised a little.Then I have my boyfriend enter me before I move my legs close enough together to cross one foot over the other.It's a little tricky at first because the fit is so tight the guy wants to go too fast and slips out,then you have to start the process over.It feels amazing for a woman(the angle directly strokes the g-spot) and men loooove how tight it feels.There are tons and tons of positions,finding the one that works for you is half the fun!Good luck!Go forth and wear a condom!