Magnetic chargers dock to two metal contacts on the toy. There is no open USB hole for water and lint to find. That makes them the default on washable vibrators that claim a shower rating.

Alignment is fussy until you learn the click. A mis-seated magnet can sit there all night and still leave you with a dead motor. Many toys glow when the dock is true. If yours does not, tug the cable gently; a seated magnet resists.

Contacts corrode if you store the toy wet. Dry them. A bit of lint on a magnet looks like a charging failure. Keep the cable; these pucks are rarely generic. When a maker discontinues a line, a perfectly good toy can become a paperweight for want of a $12 lead.

Habits

• Wipe contacts after washing.
• Do not pinch the cable in a nightstand drawer until the jacket splits.
• Buy a spare official cable while it is still sold.
• Stop charging if the toy grows hot in an unfamiliar way.