suck it!

So ladies I need your help!! I've been away from home for work for 2 weeks now and have missed my husband so much! 
He doesn't really enjoy head very much. I can never get him to finish from just giving him head... Idk if it's my technique or if it's just him not getting off for head... 
I've talked to him about it and he said I do fine and he doesn't know why he never finishes from head... but I just need advice so here's the question. 
WHAT are some good techniques that you ladies do for your special men? Maybe I can try some and get him off that way!! 
Thanks!!