We have a scene here that has some openness to interpretation.
This is from Guardians Of The Galaxy #4. That is Thanos' adopted daughter Gamora on the left, and Tony Stark (a.k.a. Iron Man) on the right.
So, is it that Tony didn't know how to show Gamora a good time?
Or...could Stark not get it up?
Notice Gamora is relatively clothed while he's hiding his lower regions under the covers and looking away.
Marvel's newest crosspromotion -- Tony Stark for Enzyte.