What does it mean if he grunts, thumps, and starts digging while he's on me?

[SaruCharmed]

Lately Ripley has been doing this while I'm holding him. It doesn't hurt or anything but it's a little startling when he does it all of a sudden and I'm worried it's a sign of aggression or annoyance. Does anyone know why he might be doing this?

 

[Flick]

When my rabbits do that, they're warning me that a nip is coming if I don't stop whatever it is I'm doing that is irritating them.

 

[cassnessxox]

The grunting and thumping sounds a bit like irritation but my girl Cleo digs everytime you put her on our puffy doona and quite often if she is in your lap and your clothes and soft or fluffy

 

[SaruCharmed]

Maybe it's because he's uncomfortable? Or because he keeps slipping down bit by bit and it annoys him so he tries to make it comfortable? I noticed that with this one bed I gave him, it was always lumpy and he didn't like it so he'd try to dig in it to make it more comfortable, but it didn't work. Ripley doesn't nip though. He's only almost done it maybe once when my hand smelled like food, lol.