Meghan Trainor says her biggest parenting fail was 'boiling' her son and giving him heat rash

First-time mom Meghan Trainor is sharing her biggest parenting fail so far to spare other moms from the same embarrassment.

The Grammy winner revealed in Ellen DeGeneres' "Mom Confessions" series that she and husband Daryl Sabara would take their son, Riley, out on morning walks. In addition to giving Riley some fresh air and sunshine, they also accidentally gave him heat rash.

"We would take him on these walks out here in California and I would come home and he would have these little red bumps all over him," Trainor, 27, said of her 9-month-old. "I sent pictures to my pediatrician after the third day in a row, and I was like, 'What's going on? I rub cream on him. I don't know what this is.'"

The "All About That Bass" singer sheepishly confessed that "I was boiling my son on my morning walks. So, don't do that!"

The Mayo Clinic said infants can develop heat rash in hot, humid weather. The biggest culprit is overdressing and the medical center advises parents to dress their infants in lightweight, cool clothing in those conditions.

The Mayo Clinic also said heat rashes generally go away on their own and advised that cool baths can help.