next time during benchpress, if she doesnt go to the DATY position, pretend to have a hard time completing the set! shell have no choice then but to spot for you which puts her right where you want her to be!
also, if you are afraid of getting a boner during stretching, wear a really tight supporter or underwear so itll be harder for lil bro to be seen! then you can completely enjoy the stretching part without worry! i know bec thats also how i used to feel when getting a legit massage from an attractive lady! once she asks me to lie on my back and starts massaging my thighs, i keep thinking "shit dont get hard! dont get hard!" and i tense up when im supposed to be relaxing! but then i get hard anyway bec it just feels so goddamn good and i get really embarrassed.