Fossas
... that Fossas have lengthy mating sessions because the male's erect penis has backwards-pointing spines along most of its length?
... that <b id="mwFik"><a href="./Fossa_(animal)" id="mwFio" rel="mw:WikiLink" title="Fossa (animal)">Fossas</a></b> <i id="mwFis">(pictured)</i> have lengthy <a href="./Mating" id="mwFiw" rel="mw:WikiLink" title="Mating">mating</a> sessions because the male's erect <a href="./Penis" id="mwFi0" rel="mw:WikiLink" title="Penis">penis</a> has backwards-pointing spines along most of its length?