A recent forum question asked which toys exerted the least pressure on one's prostate. I'd not considered that quality before so ranked my toybox in order of my own sense of increasing pressure:
peridise (zero — it has other divine applications !!)
tempo (only feel the rounded tip with I sit on it)
eupho (unstable, teasing contact with negligible pressure — my favorite)
sgx (no tail — cool intermittent pressure during 'suck-ins' or sex)
-syn (subtle, swishing swipes)
helix (moderate pressure that maneuvers to all three lobes)
mgx (encircles my prostate with balanced & cozy pressure)
classic (a 'take charge' feeling with nibs touching near the bladder neck)
maximus (no tail — nice bulk — good 'warm up' toy for Eupho)
vice (shaped perfectly for my canal — very uniform pressure)
progasm (close to my limit for total volume)
(by 'intense orgasm' I mean either a mentally, visually and spiritually intense Super-O, an extended whole-body physical experience, or a long chain of pounding dry-Os.)
All three of my 'orgasmic toys' are grouped together in the 'less pressure' portion of my list. I'd surmise though that toy mobility and the quality I call, "agility" are qualities in toys that have less mass and bulk.
Next step in the "investigation" will be to measure the mass and volume of each of these toys and see how those physical qualities stack up against my subjective impressions. Stay tuned !