I have always wondered, which part of the Nudibranch does the eggs come out from. With this sighting, I got the answers :)
Nudibranch lays eggs in circular ribbons, glued on substrate. The colour of the eggs depends on the species, usually white but can be colourful, just like the Nudibranch itself. In this case, the ribbon is blue in colour, coming out from next of its genitalia, which is located towards the front of its right side.
''Miamira alleni'' is a species of colorful sea slug, a dorid nudibranch, a shell-less marine gastropod mollusk in the family Chromodorididae. This species is found in shallow reefs in Southeast Asia. ''M. alleni'' has not been observed eating, but it is likely that it consumes sponges, like other ''Miamira '' species.