If you want to learn to bend, I recommend the Hohner Special 20. If you are using the Hohner BluesBand or other types of harmonicas and having this issue then it may be time to try the Special 20. The Blues Band is a good harmonica for beginners to get started with (sometimes it's easier for beginners in the beginning). But once you're ready to tackle bending it's a different story.
Remember that bending is tough. So be patient and you'll definitely get it over time if you don't give up. If you are a beginning harmonica student I do not recommend you work on bending until you have mastered your single note technique and can play at least one song easily.