Allowing two hours after PE is better than "releasing the tension" right away, IMHO.
nlatimer is correct about "no hard evidence" (trying to ignore that pun
) but it stands to reason allowing the accumulated blood and lymph to "stay" within the inner chambers as long as possible can't hurt in the intention of inducing the (slow) increases in the capacity of the corpus cavernosa areas within the shaft. Forcing those inner chambers to gradually expand their capacity is the premise for any successful P.E..
Sometimes (admittedly) waiting TWO HOURS can be a challenge, can't it? I found after several years plus in PE techniques, that the "urge" to finish off does diminish. It's like the body adjusts to what's being done is more physical than emotional. That "stirred up need" to release becomes less overwhelming for the most part.
Also admitting....(ahem) there can be however some occasional exceptions, of course.