You'll need lots of lube. KY Jelly is not so good. Go to some adult site or adult bookstore and buy some lube. It is much slicker and lasts longer too. I recommend getting a small buttplug and a medium buttplug because they will have a base on them and you can sit on them without worrying about them going all the way inside and not being able to get them out unless you have a partner that is patient. Then, I'd use a thin dildo or vibrator no more than 6 inches long.
Prostate orgasms are yummmyyyyyyyyyy!!!!! Love'em!!!!
Talk about blasting off....get your partner to give you a prostate massage as you jackoff or get a bj. Wow....what a rush when you cummmmmmmmmmm!!