Lets approach this issue in a primal way
Since self preservation and reproduction are the main instincts for all sorts of living forms, its really hard to work against them. Hunger, thisrt, pain, pleassure are the main signals of those instincts and are extremely hard to ignore, cause they are not only phisical but also mental and may evolve into a wide range of feelings, like anger or depression, to name a couple.
Handle with care, no1 wants to break their partners mental
Hurting yourself its a really hard task to perform. Same happens with chastity.
Both acts were performed by all kind of religions, like self hurting in order to be fit for forgiveness or withstanding mundane acts like sex dive.
On top of that, orgasms are the rewards for mating, taht is the utmost purpose for every form of life.
Also, if you are used to a regular schedule of orgasms, breaking that schdule its already a hard task to perform, either by not masturbating or having sex or... doing it more frequently.
You should think if it is an addiction, in taht case... submitting to some kind of light orgasm controll could help.. or maybe it jus tmake it worse.
Orgasm control, to my eyes, is one of the top ways of domination / submition.
The absolute goal should be, in a perfect form, something like... tanscending the need of having orgasms and being able to get them whenever its needed without being frustrated, addicted, uneasy and all the feelings that comes when you are fighting such a strong instinct.
Of course, as people suggested its a matter of trying, small stepts, and finding some1 you want to submit.
About contracts... well... im kind of like but not like them. As a personal way of thinking, i take them as a guideline, more than obligations. Just like the Pirates code LOL.
In a strict way of dealing with contracts, u can agree at first then add moddiffications to it so its a benefit for both parts
CONTRACTS CAN BE BROKEN AND MODDIFIED. They should be broken or moddifIed if one of the parts (the one giving power, usually) is not ok with it. Be sure to add the lines u need to in order to make it easier for you, like small trials or so.
About trying orgasm control, its just like gettng better at sports or some kind of new thing. I whoudlnt say "dont force yourself" since its an endurance tasks. In order to endure.. u need to force yourself and "suffer"
BUT, with endurance may come reward, you put a lot of effort and u wont be payed for them in short, benefits from sports will come with time. Also.. you mabe practice boxing (IMO one of the most demanding sports) until you become "good" at it... and then realize boxing is not for you..so its time to move to another thing.
wow... to loong... hope i make sense.