There is indeed pleasure on the spiritual path; the Buddha frequently mentions the fact that gladness and joy are necessary components of the path. But you can't be hankering after that pleasure while working to generate deep concentration. The idea is to see where you are, to know what the instructions say to do at that point, and just do that – without what Ayya Khema called 'result thinking.'
As part of the practice for entering the first jhāna, when you recognize the mind has gotten to access concentration and been stabilized there for a bit, then the next step is the focusing on pleasure. That's just part of the path. Just stay focused on the pleasurable sensation and enjoy it.
There's nothing wrong with enjoying. It's the grasping and seeking that causes the problems; being there and just staying focused on it is not a problem. But if you are actively wanting the jhāna while you are meditating, that's a hindrance and it's going to prevent you from attaining access concentration, and with no access concentration there's no jhāna possible. This is actually a great example of the second noble truth: dukkha arises from craving."
Leigh Brasington http://rc.leighb.com/more/Abandoning_the_Five_Hindrances.htm