1. Agree on a pause signal — and rehearse it once
Before anything else, settle a nonverbal stop: two taps on a hip or shoulder, a squeeze, whatever you'd both notice. Then actually try it once, in position, before you start.
One caveat worth designing around: a single agreed signal can fail — hands get busy holding you up, attention narrows, a freeze response can make reaching out hard. So keep at least one hand free or visible, and keep enough physical room that either of you can simply pull apart. The signal is a backup, and so is the geometry.