That's what we've found about the meaning of this emoji ➰ on the Japanese Internet. We have a couple of ideas which are enlisted according their feasibility. The most probable go first:

[*] In Asian languages tone has a certain meaning and is indicated in the text. So this loop can be put at the end of a word, showing a specific intonation, which may suggest a good mood.
[*] A simple explanation: this loop Illustrates what is drawn on the icon, a loop. It is often used in conjunction with other emojis: ➰❣️ , ➰🍂 , 🐔➰🐣➰🐤➰🐔.
[*] Indicates a USB connection.
[*] Presents a wrapper for rice balls 🍙 that are eaten at night.