Why do my geese keep doing this?

So I have 6 geese. They are very friendly and will allow almost anyone that they are familiar with to pet them. When night comes, they absolutely love me to scratch their heads and will usually fall asleep like this. But there is a problem. Every single time when I'm near them, they will come to me and start chewing on my pants, especially if they have buttons. This happens to anyone, wether it's pants or a dress. They just seem to love munching on clothes. This wouldn't be an issue, but their love for fashion can hurt as they can pinch the skin pretty hard, so hard that sometimes there will be blood. They won't bite the hand if I touch them while they're chewing on the pants. I can actually do anything to them and they don't seem bothered. I even lifted them and extended their wings and all they did was stop for a sec to check what I'm doing and then resumed the munching.

What's going on with my geese? Is this how they show affection (if geese even feel affection)?