Penis Plugs

I recommend against inserting anything into your urethra. Unlike the rectum, the urethra is supposed to be sterile. Violating your urethra is a great way to get a urinary tract infection (UTI), In case you don't know, these are very painful and can in some cases lead to chronic infection and pain problems.

It is possible that because these plugs only go in a short distance that their risk of UTI is low, but I would do careful research before playing with these. Once you have a UTI you will wish you never did.

Darwin

Don't ever stick or squirt anything of any kind into your urethra. Like @darwin said, it is supposed to always be sterile, and any violation of that WILL cause you trouble sooner or later! If your "anerosing" doesn't seem satisfying enough to you, focus your efforts on deepening the experience through further study and practice. Titillating yourself with superficial stimulation just to further intensify the experience is actually counterproductive, pulling you back into the old penis-centerd paradigm instead of facilitating further forward progress on this amazing journey. Think about what you are really seeking and why, especially before deciding to incorporate such a high-risk activity into your practices.

Pureevoke,

I have to side with both @darwin & @Thruster here. I understand the curiosity and desire to explore a wide range of sensuous experiences but that curiosity always needs to be tempered with a concern for personal safety and negative consequences. As @darwin pointed out the potential for developing UTI's is always present regardless of how diligently you prepare trying to be sterile. You are playing Russian Roulette with your body here, PLEASE think twice before engaging in such action. The consequences for harm far out weigh the limited amount of additional stimulation you might receive.

Likewise, @Thruster, makes a very good point about the potential for distractive stimulation taking focus away from the prostate sensations and putting focus back on the penile sensations. This may be very counterproductive to your established rewiring with Aneros. I would strongly advise you not to add penile stimulation of any kind to your solo Anerosessions as this can only draw focus away from the prostate and back to the traditional masturbatory orgasmic path.
Good Vibes to You !

i sounded usin a slim glo stik b4. about 12" all the way in. feels 'different'. uncomfortable but pleasurable.use water based lube, and NEVER USE SPIT

It's worth repeating -- Don't ever stick or squirt anything of any kind into your urethra!