Two moves to hit your oblique abdominal muscles - those ones that suck you in and give you a waist just made for bikini weather.

Oblique raise

Side Lying Reach:

On a mat, or towel, lie on your side with the arm closest to the floor stretched out straight in line with your chest for support
Hips, knees and ankles must be positioned in a straight alignment (not leaning back or forward)
Breathe in, exhale and reach your upper arm towards your ankles as you raise your head and chest in that direction (body still in a straight line)
Release slowly and repeat!
Option, as pictured above, to have support under the body. Preferable just to keep your arm outstretched for support.

Oblique abdominals

Position yourself as in steps 1 and 2 above. Lower arm is stretched out in line with body, palm down
Breathe in, exhale - brace abdominals and raise upper leg just above hip height - no rocking forward or back!
Advanced, raise both legs to meet, breathe in, exhale and lower. Repeat
Option, raise top leg and then reach upper arm and head towards ankle for a double side crunch


Mermaid stretch

Stretch! Extend legs as wide as you comfortably can and stretch towards each ankle in turn. Hold for 20 seconds. Repeat if feeling particularly tight through the sides and lower back.