Former Prince Andrew Tosses Boobie Ball with Kid in Pics

Andrew Mountbatten-Windsor -- formerly known as Prince Andrew -- turned fun bags into kicks for kids in some very un-princely photos obtained by TMZ.

These pics of Andrew, taken back in 2011, show the then-Duke of York kneeling across from a young boy and rolling a ball back and forth with him.

Just clean, wholesome fun ... until you realize the ball is painted like a breast, complete with a pale pink nipple protruding from it.

The young boy appears to be horsing around with the boob ball while Andrew crawls around on a rug across from him in several of the snaps. A later pic shows them sitting together on a couch.

Our sources say ... these pics were taken inside Andrew's Windsor residence a little more than 15 years ago. We're also told Andrew was not alone with the child.

As you know, Andrew was arrested Thursday -- his 66th birthday -- on suspicion of misconduct in public office ... with alleged emails he sent to Jeffrey Epstein regarding his role as UK trade envoy in the early 2000s reportedly being central to the investigation.

To be clear ... his arrest has nothing to do with the myriad sexual misconduct allegations made against him over the years.