Hand Friend

Vol.3 Chapter 14: Hand in Hand
Vol.3 Chapter 13.5: Impatience
Vol.3 Chapter 15: Conclusion
Vol.3 Chapter 13.5: Impatience
Vol.3 Chapter 15: Conclusion
Kagura already has a girlfriend. But Hosoya, the girl who sits next to Kagura, offers him a "tefure" relationship. What kind of relationship is this?