I have 2 boy Guinea pigs that are just over a year old now. One of them is very quiet, laid back, likes a cuddle every now and then etc. the other one is the more outgoing one, will come and hop on me for a snooze, fuss , gives me licks….but…. He’s started to come and hop on me and nip my neck or shoulder. He very rarely makes me bleed but it does hurt. I tend to lift him off me and not stroke him or anything for a couple of minutes. Why would he be doing this? He doesn’t do it to anybody else really.