I urge everyone to bookmark that blog; it is always a fascinating tour of the weirder and wonderfuller places on our planet. And let me leave you with this simply jaw-dropping video of undulatus asperatus in action.
(A sunscreen with a physical block like titanium dioxide or zinc oxide can be applied last, after a serum or moisturizer.) Apply a serum next and, finally, moisturizer if you need it. Polis also recommends serums or sunscreens with moisturizers built in because they save time.
I have been using this product alone after washing, but want to add a serum like the PTR camu camu or maybe other. I'm too oily and do not wish to add a moisturizer twice or even once a day. Serums are lighter but I don't know if the combination might be counterproductive or something.