With or without a chastity device I like this kinky "bottoms don't get to cum" rule.
I always find it hot to see pictures/videos where the cock of the guy getting fucked is completely ignored and untouched. Either the bottom's cock is hard and he is very horny and frustrated or the bottom's cock is completely limp - either option is exciting as long as the bottom's cock does not get touched at all.
I think this rule is hot because the bottom not getting off exaggerates the difference between the experiences of the DOM (top) and the SUB (bottom). It shows that the bottom is focusing 100% on pleasing the top - not playing with his own cock.
To make the "bottoms don't get to cum" rule even more unequal, humiliating and humbling for the SUB I think it is hot if after the sex is over and the DOM (top) has enjoyed his wonderful orgasm(s) the two guys cuddle. Then during the cuddling the bottom boy thanks the man (top) very much for the sex and he talks at great length about how good the sex was EVEN THOUGH HE DID NOT GET TO CUM. The top man either continues to ignore the bottom boy's cock or perhaps the top man slowly edges and teases the bottom boy's cock a little - but he makes no effort to get the boy off and the boy very submissively does not ask to cum - he remains completely focused on the man's pleasure and on thanking the man for the sex.
On a related note, I think it is very kinky if the top man tells the bottom boy BEFORE THEY START TO HAVE SEX that the boy will not be allowed to cum DURING or AFTER the sex but if he really really wants to cum then he is allowed to very quickly jack off and cum BEFORE the sex starts. Thus, if the bottom boy decides that he wants to have an orgasm he must very quickly JO and squirt his cum as fast as possible - no wasting time doing it slowly. Then after the boy squirts his cum he will clean up his spunk and focus on giving the top man pleasure. The bottom boy might discover that it's not much fun getting ass fucked shortly after orgasm, so perhaps the next time he will decide to skip the offer of pre-sex JO and go without orgasm entirely.
If anyone is curious to try chastity you can buy some very inexpensive chastity devices on
www.dhgate.com - but note that items are shipped from China so you must be prepared to wait two weeks to receive your device.