Thank you thank you. So, I notice the first one has a little "tilt" to it, does that mean I need to do anything special with it?

you're welcome. I have a few more points that may help.

it's designed to be able to find the P-spot. after insertion, gently explore for it, just ask how it feels, it should be obvious when found. Also, the first one comes in two lengths. There's a wristwrap (kind of like the wiimotes actually) please use it. This toy doesn't have a wide base and could get sucked up the colon if let go. if using an anal probe on a partner is anything like using a vibrator during oral sex, it may tire and/or cramp the hand making it more likely to slip out. Try using whatever toy you decide on in conjunction with oral sex, or, if you want something to use during vaginal intercourse, buy a plug or probe with a WIDE base.

While I don't know personally, I have read other users here talk about walking around with plugs in, so it might be possible if it's big enough.

Definitely!

In my experience it's more for 'filling' and 'orgasm-enhancing' than for actually giving a prostate orgasm, though.

For a plug to be used by a guy during sex, I'd recommend the Pure Plug (Medium is good, if that's his size).