Get permission
If this is what you want (as husband, wife or boyfriend, girlfriend), you must get permission. If you pull out a rocket that's 12 inches long and 10 inches in circumference, she'll probably scream and run away. Talk to her about your fantasies. Tell her your wishes. You never know, she might have the same desire.

Take it easy
When using a huge dildo, you have to start slowly. For example, start with a dildo or vibrator that's a few inches thicker than you're used to. From there, you can buy bigger and bigger toys until you get the monster sex toy of your dreams. Again, you're not stretching your vagina, just training yourself and your vaginal muscles to relax.

Use lots of lubricating oil
When using a large dildo, you need to have plenty of good lubricant on hand. This way, you can avoid small cuts or tears in the vaginal opening and labia and ensure a comfortable ride. However, be sure to use the correct lubricant for the job. This article will teach you to choose the right lube. Click here and scroll down to #4!

let her take the lead
Finally, when using a big dildo on your partner, you have to let her take the lead. If not, this force can cause pain and tearing. So, the best thing you can do is stimulate her clit, play with her nipples, do something to get her hot while keeping the dildo in place. The more excited she is, the more she will open and pull the dildo in.

Most importantly, arousal is key. Before you start, make sure she's completely hot, fretful, and ready to go. Otherwise, her vaginal muscles won't relax enough to use a big dildo.

Vaginal stretching is a normal desire
The desire to use a big dildo and the fascination with vaginal stretching are completely normal fantasies. So, don't worry that you're a twisted fetish who needs to bow his (or her) head in shame. There are a lot of people out there just like you, and a sex toy industry that caters to this particular problem.

So share your fantasies with your partner and let the exploration blossom from there.