My friend kc upset should she be?

she was being y flirty with her BF and I don't know I guess he might be in a mood...but again I don't know she's texting it's hard to tell...she told him she was going to rub herself because they r doing y talk...he responds make sure u use lube? she kind of was upset about it but I said I don't know maybe he was giving u tips or something I don't know..plus maybe he's teasing...should she feel this way or what do you think? she can't call him cause he can't talk on the phone at this hour only text cause of his mom.