Earphones looks like you are tracing the band of a pair of headphones, then outlining the ear cups. Start with your two index finger on the crown of the head and trace down toward your ears. Then make your hands into cups and touch them around your ears.
An alternative sign for earphones (more for earbuds that come with your smartphone) is to point each index finger directly at either ear at the same time, minus the tracing around the head.
Babies love any kind of accessory or jewelry you may be wearing. Teach them the sign for earphones so that they can ask for the earphones instead of grabbing at the earphones.
Use this sign to introduce your baby to technology in combination with their portable video set in the car, or at home when watching their signing times music videos.