I start my students off with "defensive sparring". They sometimes don't even have a functional strike at this point. But they've been introduced to basic footwork, balance principles, and moving in/out of clinch distance. That's all they get to use, while a partner (me, for at least the first session) brings a steady stream of light-touch attacks. The student's job is to find ways to control distance and angles without hitting or grabbing. This also lets them start getting used to being "in the storm". Over time, the intensity increases, and the intention is for students to keep returning to this drill even when they have the tools to retaliate.
And for the partner, it's a chance to practice staying on the offensive. I've had so many people come to me with a habit of taking turns (I enter, strike, then back off and defend as you do the same - then repeat the cycle). Some (not all) at least have some combos, but they have the habit of backing off for no reason. This offense-only drill makes them practice looking for openings while still attacking.
Of course, even though they'll return to this drill over time, they do progress to sparring, which eventually includes randori (standing grappling) and rolling (ground grappling).