Sri Aurobindo
Letters of Sri Aurobindo
Volume IV - Part 3
The idea of the new European mystics like Lawrence and Middleton Murry etc. is that the indulgence of sex is the appointed way to find the Overself or the Under Self, for that is what it 
really seems to be! Brunton of course knows better. But if the personal Overself is all that is wanted and not the Divine, then sex and many other things are permissible. One has only to realise that one is not the body, not the life, not the mind, but the Overself and then do whatever the Overself tells you to do.