Errr, are you aware of what distension means? I presume you were trying to say "lack of sexual tension", but in English the morphology doesn't break down that way: distension is the nominalization of "to distend", i.e. to swell or inflate by pressure from within. So 'sexual "distension" can only mean having a raging hard-on.
A better word for what you were trying to say might be "sexual contentment".