How did Solar and ChangSub become close as friends?

Similarities between Solar and ChangSub that make them '91 friends.

ORDER Moonbyul's Cheese In The Trap album:
[Fansite Discount] All 3 Versions $22.16🔗 https://www.ktown4u.com/iteminfo?grp_...
ORDER Wheein's Fanmeeting Tickets:
[Pricing]
Offline: http://ticket.yes24.com/Pages/English... (77,000KRW, Yes24 Live Hall)
Online: http://ticket.yes24.com/Pages/English... (Pt. 1) / http://ticket.yes24.com/Pages/English... (Pt. 2) (33,000KRW)

International Moomoo discord:
🔗  / discord  

Twitch:
🔗  / nynahnina  
Thursday 1pm CST
Friday 2pm CST


If you really appreciate what I do, you can buy me a coffee! McDonald's coffee in Chicago is only $1!
🔗https://ko-fi.com/nynahnina

Twitter:
Follow @MamamooCharts for fast updates on Mamamoo comeback
Follow me @NynahNina:
🔗  / nynahnina  
For business inquiries:
[email protected]
My Discord:
🔗  / discord  

Sources:
Eng Sub Videos:
🔗https://docs.google.com/spreadsheets/...