The intent is to restrict a person's oxygen
I have no idea how & why someone would have a sexual fetish around strangling, but when it comes to the law on murder, the 'intent' to convict someone of murder is 'the intent to kill'.
As to the mechanics of strangling someone in order to cause their deaths, I'd have thought it would be like you see in film & tv fiction - but I recently came across this exchange in a court case between a defence barrister and a forensic expert witness - discussing injury to something called the vagus nerve.
"Q. So it rather looks as if pressure to the neck is a pretty dangerous business?
A. It - certainly from my practice I know and from reports recorded in the forensic literature, there is no safe way to squeeze someone's neck. It always carries with it the risk of this stimulating these receptors and producing this vagal response.
Q. We can all understand that if you are choking someone, in the sense that you are restricting either the blood flow or the airflow in either of the first two ways, the vascular or the respiratory are potential ways of strangling someone but it is going to take time?
A. Yes.
Q. And there may be some sort of struggle or the opportunity to say: "I can't breathe"?
A. Yes.
Q. What about the vagal inhibition method, how does that affect that scenario?
A. If it kicks in at the level that we have mentioned, where there is a severe effect on the heart, causing it to slow right down or causing it to beat abnormally or causing it to stop, there is no prior warning to that; that will occur out of the blue.
Q. And is the situation therefore that someone may literally drop dead?
A. They may literally drop dead with the pressure being applied to their neck, and there are recorded cases of that occurring within the forensic literature."