Commission from Sir Lagalot! twitter/Sir_Lagalot_
Ungagged version here:

It is autumn in Gensokyo, and there have been numerous amounts of bondage related ‘incidents’ that have taken place near the Youkai Mountain. There was some talk among the youkai residing there about the occurrences, and Hina Kagiyama had her interest piqued regarding the devices used when she observed them being used during the ‘incidents’ (she saw what happened to Aya+Momiji but didn’t intervene as well as Sanae’s ‘display’ at her shrine).
Hina went to see her friend Nitori Kawashiro near the Genbu Ravine to talk about the ‘incidents’ that have been occuring, and Nitori explained that it was her who was designing the ‘armbinder’ devices for use. Hina was intrigued by what Nitori mentioned, and because of her curiosity, she asked Nitori if she could try out the armbinder for herself. Nitori asked if Hina was willing to act as somewhat of a ‘bondage doll’ and redirect anybody who asks about the armbinder to her shop, and Hina happily agreed as she could gather some more support for her friend’s side business. After taking her measurements, Nitori sent Hina off so she could start working on the armbinder for her.
After a couple weeks, Nitori finished the armbinder for Hina, and headed off to meet with her near the river at Youkai Mountain. Hina asked if Nitori can help her into the armbinder, as well as tying her ribbon around her mouth so she can silently experience being outside in bondage, and Nitori helped her out on her request. After a while of spinning around by herself, Hina gestured for Nitori to remove her ribbon gag, and she gave the go-ahead to leave her in bondage like this and come back by the end of the day to help her out. Nitori bid farewell, and left Hina to happily spin by her own devices right near the end of the river banks!