Gypsy Rose Blanchard is reacting to Mackenzie Shirilla having hookups and getting hickeys behind bars ... saying kissing women is one way to make the days go by.

Gypsy sat down with TMZ's Charlie Neff on The TMZ Podcast and told us Mackenzie Shirilla having girlfriends in prison is pretty standard, but it's good for one thing only ... passing time.

Check it out ... Gypsy says Mackenzie needs more than a hookup ... telling us it would do a lot of good if an older inmate took Mackenzie under her wing. After all, it worked for Gypsy.

GRB knows what she's talking about here ... she kissed plenty of women in the slammer, but insists things never went past first base.

Mackenzie's got at least 15 years to kill after being convicted of killing her boyfriend and their friend in a car crash ... and Gypsy, who did hard time for her role in murdering her mother, tells us she would never connect with Mackenzie if she gets out on parole.