Pretty simple and straightforward question, what rating would a game get for something like this?
The age rating system for games and movies is not just a max() function where the highest offending item sets the rating.
Some things will automatically give you an Adult-Only rating and some will automatically go to PG or Teen, but there's a vague point system for intermediate ratings.
These rules changes often and some of the items are somewhat subjective and will be slightly influenced by the reviewer and the target market. Australia, America, Europe, China, Korea, and Japan to name a few regions all have different rating/point systems. It also depends on cultural factors and current political mood.
The answer is there is no answer: For the final items it's often a back-and-forth with the review board (eg: "tone down one of those 3 items") to reach the target age rating.
Poking nipples (regardless gender) are generally around the everyone/teen (age 10-14) rating range due to the surrounding context and overall tone of the game that often goes with it but adding too many other risqué items can raise the rating and even then it varies by cultural region.