The well know hippieflip scenario.
This combo is a true mystical experience full of euphoria.
Expect less ups and downs and confusing from the shrooms, and a stronger feeling of concentration. The profoundness can be very overwhelming and a strong urge to explain others around you what state is going through you is pretty much always occuring.
Make sure as long as the shrooms are at it's peak that you don't have a come down from the E, that feels really awful. MDMA as a chemical and shrooms as a product from mother nature is the only contrast that might cause unwanted emotions apart from both the negative sides from the drugs on it's own.
Psysically it's essential that your carbohydrate level don't get empty, during your trip, fast absorbing sugars such as fruit drinks are working well for this.
Water prevents you from getting dried out, but watch out that you don't drink too much since this may can cause a low salt level as well.
If you get dizzy and a feeling of falling unconsciouness, drink sugars. If you feel a dry tongue or throat drink a lil bit water.