Soda: 
He most definitely join in with you and sing with you..at the top of his lungs 
Ponyboy: 
He would sing with you then lay down on your lap as you sing
Johnny: 
To him your voice is sooo beautiful..he would probably fall asleep on your lap while listening
Dally: 
Would sit there and smirk ,he won't admit he likes your singing but he dose.
Darry: 
He would probably hug you from behind and sing a with smoothly 
Two-bit: 
Would sit ont eh floor like a lil kid and listen 
Steve: 
To I think he would sit there, eat cake and smile
                                      
                                          
                                   
                                              
                                           
                                               
                                                  