I use a P.E.S. box. I do lots of HFO's with it (P.E.S. prostate anal stimulator and cock ring) and also lots of ghost fuckings (P.E.S., Zeus or Rimba plugs.) For me, it has enough power, if it had more power, I would be tempted to turn it up higher.
One way I use it is a prostate anal stimulator is up my asshole, ring on the head of my cock, and standing at the washbowl counter. I spread my legs some so I put a little strain on my groin, then I lean forward with my balls on the counter pressing against the vanity edge, so the edge is pressing up against the root of my very hard dick.
Then, I lean down some, so my balls are pressed against the counter a bit. I then play with my hard tits, tickling and pinching my tits, and sometimes with large binder clips on my tits.
I slowly crank up the P.E.S. box and I have it marked where HFO occurs. HFO is "not" at max.
As I get closer to cuming, my dick gets a little blue and then a ting of purple because I have such an intense hardon. It's very very very hot to watch my dick, and also me in the mirror. I can see all of the action, and with the wall mirror behind me, I can see the electrical wire connected to the prostate stimulator up into my ass!
Then, I cum, I can feel it building up and up with some more tingling sensations in the base of my cock, often my whole body shakes when I cum, it is so intense. Then, sometimes, I back off on the P.E.S. box and let my cock and asshole stim a bit, I have such a horny asshole all of the time.
Sometimes I make sure my bladder is full, I think this adds to the pressure/intensity. Also, when doing this, sometimes I pee into a glass some, I think this helps the electrical conductivity from the head of my dick down into my prostate. Just be sure to pee into a glass and not down the drain where you might get some kind of a ground connection with the drain pipe and maybe a shock. Also, be careful everything is below the waist. Sometimes, if I'm really hot, I drink my pee for the taboo feeling. I use my P,E.S box on the mains with the P.E.S. supplied and safe transformer on a surge suppressor. This gives more output than with just the battery. It is quite noticeable at the higher power settings.
Sometimes I also do this when I need a BM, and I also have a full bladder. For those sessions I sit on the toilet lid with a plastic bag on a towel on the toilet lid in case some mess comes out of my butt, which really doesn't seem to happen too often. Having the P.E.S. box going on a prostate stimulator up my asshole, ring on my cock, and a full bladder and the need for a BM is very very hot and with a HFO. There are some pretty good sensations bearing down for a BM with a full bladder and the P.E.S box pulsing your prostate and the head of your dick while doing some good tit action.
I know what I'm doing tonight before bed! LOL! I'm getting hard now just writing this up.