Sunderland thus missed the chance to register a much-needed win in their quest to avoid relegation, and Coleman admits that his charges appear in danger of conceding far too often.
"We came back from [the penalty] and showed some spirit," the Welshman told the Sunderland Echo. "I thought we would score again if I'm honest, it went quite here, Reading had a dip.
"That is the difference, in that bottom three, when the points are there with 20 minutes to go.
"You want it to go for you, you are wishing away all the negatives. If you are in mid table or top 10, your thinking is different, more positive.
"At the moment we look fragile, for all our effort and endeavour. Those one or two moments in one or two games when you are asked a serious question, one goal in it, we look like we can concede and it happened."
Sunderland have dropped to the bottom of the Championship table following the Madejski Stadium draw, six points from safety with three games left of the campaign.