My original tumblr post was here. These animations were researched by Bacchus at ErosBlog as part of the “Δ commission.” The research was originally published at Hedonix as “Δ 048 The Rubber Mask Reveal.” Here is what Bacchus found.

The source Tumblr post in this image’s chain of Tumblr attribution offers these two tags: “#ULTRAMAN #TOKUSATSU”. According to Wikipedia Ultraman (variously ウルトラマン or Urutoraman) was a Japanese sci-fi television show in the tokusatsu style that aired in 40 episodes in 1966 and 1967.

From the Wikipedia summary there appears to have been only one regular female character on the show, played by actress Hiroko Sakurai (樱井浩子). An image of her found here looks sufficiently similar to the girl in the animations for me to tentatively conclude that she is indeed the actress seen wearing the rubber alien mask: