I'm a HUGE Dekang fan but not all of their flavors. I've only tried the mango that you bought and it was bland compared to the US vendors that make their own. I really like their DK-Tab, 234fatsal (clove but very strong), ginseng, 3&5, red apple, caramel, melon, watermelon, and tobacco. There are others I've tried but just too many to list. Like all juice, some are good and some aren't.
As for steeping, once you get it, it's as steeped as it will get. Dekang comes in 100% vg, 50/50, 70pg/30vg, 80pg/20vg, and 100%pg (harsh on the throat). It may be the higher pg that isn't making the juice taste right to you.
Also, I've found with them, only use one juice per day. I can't explain why but it works. Some of their flavors like RY4 seem bland and tasteless to me unless it's the only Dekang juice that I vape that day...then the flavor bursts open.
As for steeping, once you get it, it's as steeped as it will get. Dekang comes in 100% vg, 50/50, 70pg/30vg, 80pg/20vg, and 100%pg (harsh on the throat). It may be the higher pg that isn't making the juice taste right to you.
Also, I've found with them, only use one juice per day. I can't explain why but it works. Some of their flavors like RY4 seem bland and tasteless to me unless it's the only Dekang juice that I vape that day...then the flavor bursts open.