I’m sorry to say that neither of us remembers that specific fic. However, I went ahead and combed through our masterlist and all of the Shelnard fics on AO3 to amass some links to fics containing ‘top’!Leonard for you! Hopefully this helps. :>
(Warning: these are rated M at minimum.)
More Bang for Your Buck (though I included this because Leonard ‘pitches’, it’s actually more of a bottom!Leonard fic)
Leonard’s Spot (part 2 of the The Spot series)
Red Shirt (part 7 of the Whatever Works series)
Bonus! Sheldon tops, but they stealth!bang in 4A while both of their mothers are visiting.