I love this cutie like you wouldn't believe.
Taking a quick glance at the exterior of Shroomish, it's clear the opening topside is for the expulsion of spores, and we can assume that at least one unobserved opening exists below deck for the purpose of laying eggs (which they canonically do). Although Shroomish are not completely radially symmetrical, we can reasonably assume that all three orifices are internally connected like a sideways T-shaped pipe, as Shroomish will need to divert significant portions of the composted soil they consume toward both spore production up top and egg development down under. That gives us a minimum of three acceptable connected orifices for cock insertion, but I'd like to make the case for the orifice below deck if I may. Just musing upon it... I'm elated! Though loyal once captured, ordering little Miss Mushroom to choke on your redwood like a lusty lumberjack is uncouth, especially when considering your girth. At the end of the day, your pleasure need be matched by hers for a healthy relationship going forward. Given that Shroomish have been regularly documented enthusiastically expelling spores from their hollow up high, that hole appears perfect for spewing the gushing volcano of cum that you MUST give her. Let's imagine! Noticing your lack of clothes and supine position, without hesitation Shroomish waddles from your ankles to your shoulders, slowing in the middle to purposefully, gently glide her supple underbelly along your stiffening shaft. She begins to back up, but what's that? She encounters the Rod of Resistance. Undaunted, She takes it. Mounts it. Slowly. She goes down. Up. Now down. Up and down. Such a fine rhythm. It's welling up. She clenches. Tighter now. Do it. Tighter and tighter. Do it! Cum is such a pleasant scent on its own, but infinitely enhanced by the aroma of fallen leaves. We all have our reasons, but I hope you know why Shroomish will always be my best friend.