Proximity question

I teach high school students English and this year I'm planning partner speaking and reading activities. I was thinking of using the phrase elbow to elbow and knee to knee to teach how close you need to be to focus on the partner yet quiet enough not to distract others. For my Muslim students would this create any discomfort and also should I make sure to avoid opposite gender partners? My students are aged 14-19, classes mixed of all ethnic backgrounds.