This fic is somewhere on AO3, and it is not tagged "sex pollen".
It involves Steve and Bucky being the only two people in New York not affected by some sort of aerosolized aphrodisiac. Bucky's just back from a mission, and they have to make their way from Brooklyn to Avengers Tower on foot. They don't have sex while the aphrodisiac is in effect, though they both want to, but Talk It Out later.
Other pairings include: Tony/Pepper/Bruce, Natasha/Clint/Maria Hill, and Jane Foster/Thor - Jane's actually the one who figures out the solution, since it wore off her earlier.
At one point, Tony hits on Steve and compares him to a nice car.
Does anyone happen to remember what fic this is?