New York Gov. Mario M. Cuomo has begun getting some flak from fellow Democrats who are telling him that if he's serious about being a noncandidate for president, he ought to learn to behave like one.

Last week, during a political trip to Cleveland, Cuomo fell into a conversation with Cuyahoga County Commissioner Tim Hagan. According to Hagan, Cuomo asked him what he should do "in light of the fact that some say my speaking out . . . diminishes the other candidates?"

Hagan, who had urged Cuomo to get in the race, said he told the newly peripatetic governor that "you're absolutely detracting from them. My advice to you, cold-hearted, is if you're not going to run, stay in the state of New York. You can't have it both ways . . . . He was a little taken aback."

The conversation prompted Cuomo to telephone Democratic National Committee Chairman Paul G. Kirk Jr. and inquire whether he should issue a Shermanesque statement shutting the door to all possibility of a draft.

According to sources in New York, Kirk said that might be advisable. But when Cuomo asked whether former Virginia governor Charles S. Robb and Sens. Bill Bradley (N.J.) and Sam Nunn (Ga.) should and would do the same, Kirk said that was unlikely, the sources continued.

Kirk was unavailable for comment.

Cuomo acknowledged calling Kirk to "seek advice" but declined to go into more detail. He added, however, that he has "not received a single complaint from any candidate or from anyone working for a candidate" about his globe-trotting, debate-hosting, speechmaking ways.

"I don't want to be a candidate," he insisted. "I don't hope secretly for a brokered convention. Just the opposite, I hope desperately that one of these candidates will emerge." The presidency, he added, "is a terrible, terrible burden . . . . If the burden were clearly assigned to me, I would do it. I hope it is not."

And one more thing: "I've just canceled an appearance in New Hampshire."