Is it normal to talk under the covers/blanket in bed?

so when im in bed, tired and resting under my duvet, someone comes in like my mom or whatever and I stay tucked under my duvet. my moms okay with this and has no problem but the other day my sis barged in looking for something and was asking where it was and was like ''I cant talk to you under a fucking duvet'' is it an eye contact issue? do some just demand to have eye to eye in all social situations? if its a serious conversation then yeah I will sit up and take notice but if youre just looking for a book or whatever...then i'll stay under my duvet! for me its a comfort thing.