Spacing rhymes with:
pacing, pasing, basing, bracing, casing, chasing, debasing, defacing, displacing, effacing, embracing, erasing, facing, gracing, misplacing, pacing, pasing, placing, racing, replacing, retracing, tracing
Spacing sounds like:
savaging, sobocinski, spasms, speaking, specimens, spicing, spiking, subconscious, sufficiency, suffusing, supposing, suspicions