The problem of spin-decoupling spin $I=1$ nuclear with large quadrupolar splittings ${\ensuremath{\omega}}_{Q}$ (e.g. deuterium) from dilute $S$ spins via double-quantum transitions is dealt with. The normal two-spin-\textonehalf{} single-quantum decoupling problem ($I=\frac{1}{2}$, $S=\frac{1}{2}$) is first dealt with as a reminder of the coherent averaging approach and to understand the dependence of the $S$-resonance linewidth on the $I$ rf field intensity (${\ensuremath{\omega}}_{1}$) and resonance offset ($\ensuremath{\Delta}\ensuremath{\omega}$). The double-quantum problem ($I=1$, $S=\frac{1}{2}$) is then treated analogously by introducing fictitious spin-\textonehalf{} operators for the $I$ double-quantum transition. The decoupling condition is found to be very sensitive to the spin-$I$ resonance condition and to go as $\ensuremath{\sim}\frac{1}{{\ensuremath{\omega}}_{1}^{4}}$ with the spin-$I$ rf field intensity at resonance in the double-quantum regime (${\ensuremath{\omega}}_{1}\ensuremath{\ll}{\ensuremath{\omega}}_{Q}$). Experimental examples on heavy ice, dimethylsulfoxide-${d}_{6}$ and benzene-${d}_{6}$ are presented verifying the quantitative theoretical predictions. Extensions to higher-order multiple-quantum effects for spin $I>1$ and for several coupled spin-\textonehalf{} nuclei are discussed.